diff --git a/src/PhpSpreadsheet/Reader/BaseReader.php b/src/PhpSpreadsheet/Reader/BaseReader.php
index 83e1b6f18..46e25d042 100644
--- a/src/PhpSpreadsheet/Reader/BaseReader.php
+++ b/src/PhpSpreadsheet/Reader/BaseReader.php
@@ -112,11 +112,13 @@ abstract class BaseReader implements IReader
         return $this;
     }
 
+    /** @return null|string[] */
     public function getLoadSheetsOnly(): ?array
     {
         return $this->loadSheetsOnly;
     }
 
+    /** @param null|string|string[] $sheetList */
     public function setLoadSheetsOnly(string|array|null $sheetList): self
     {
         if ($sheetList === null) {
diff --git a/src/PhpSpreadsheet/Reader/Csv.php b/src/PhpSpreadsheet/Reader/Csv.php
index 325e3723f..f4cdd02d3 100644
--- a/src/PhpSpreadsheet/Reader/Csv.php
+++ b/src/PhpSpreadsheet/Reader/Csv.php
@@ -228,6 +228,7 @@ class Csv extends BaseReader
         $this->checkSeparator();
         $this->inferSeparator();
 
+        /** @var array<int, array{worksheetName: string, lastColumnLetter: string, lastColumnIndex: int, totalRows: int, totalColumns: int, sheetState: string}> */
         $worksheetInfo = [];
         $worksheetInfo[0]['worksheetName'] = 'Worksheet';
         $worksheetInfo[0]['lastColumnLetter'] = 'A';
diff --git a/src/PhpSpreadsheet/Reader/Csv/Delimiter.php b/src/PhpSpreadsheet/Reader/Csv/Delimiter.php
index 348331e35..05b898fc4 100644
--- a/src/PhpSpreadsheet/Reader/Csv/Delimiter.php
+++ b/src/PhpSpreadsheet/Reader/Csv/Delimiter.php
@@ -13,6 +13,7 @@ class Delimiter
 
     protected string $enclosure;
 
+    /** @var array<string, int[]> */
     protected array $counts = [];
 
     protected int $numberLines = 0;
@@ -53,6 +54,7 @@ class Delimiter
         }
     }
 
+    /** @param array<string, int> $delimiterKeys */
     protected function countDelimiterValues(string $line, array $delimiterKeys): void
     {
         $splitString = mb_str_split($line, 1, 'UTF-8');
@@ -69,7 +71,7 @@ class Delimiter
         // Calculate the mean square deviations for each delimiter
         //     (ignoring delimiters that haven't been found consistently)
         $meanSquareDeviations = [];
-        $middleIdx = floor(($this->numberLines - 1) / 2);
+        $middleIdx = (int) floor(($this->numberLines - 1) / 2);
 
         foreach (self::POTENTIAL_DELIMETERS as $delimiter) {
             $series = $this->counts[$delimiter];
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric.php b/src/PhpSpreadsheet/Reader/Gnumeric.php
index 2019d9a09..ed932388c 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric.php
@@ -38,6 +38,8 @@ class Gnumeric extends BaseReader
 
     /**
      * Shared Expressions.
+     *
+     * @var array<array{column: int, row: int, formula:string}>
      */
     private array $expressions = [];
 
@@ -48,6 +50,7 @@ class Gnumeric extends BaseReader
 
     private ReferenceHelper $referenceHelper;
 
+    /** @var array{'dataType': string[]} */
     public static array $mappings = [
         'dataType' => [
             '10' => DataType::TYPE_NULL,
@@ -96,6 +99,8 @@ class Gnumeric extends BaseReader
 
     /**
      * Reads names of the worksheets from a file, without parsing the whole file to a Spreadsheet object.
+     *
+     * @return string[]
      */
     public function listWorksheetNames(string $filename): array
     {
@@ -203,6 +208,7 @@ class Gnumeric extends BaseReader
         return $data;
     }
 
+    /** @return mixed[] */
     public static function gnumericMappings(): array
     {
         return array_merge(self::$mappings, Styles::$mappings);
@@ -559,8 +565,8 @@ class Gnumeric extends BaseReader
             if (((string) $cell) > '') {
                 // Formula
                 $this->expressions[$ExprID] = [
-                    'column' => $cellAttributes->Col,
-                    'row' => $cellAttributes->Row,
+                    'column' => (int) $cellAttributes->Col,
+                    'row' => (int) $cellAttributes->Row,
                     'formula' => (string) $cell,
                 ];
             } else {
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
index f12b742f3..8315aa577 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric/PageSetup.php
@@ -70,6 +70,11 @@ class PageSetup
         return $this;
     }
 
+    /**
+     * @param float[] $marginSet
+     *
+     * @return float[]
+     */
     private function buildMarginSet(SimpleXMLElement $sheet, array $marginSet): array
     {
         foreach ($sheet->PrintInformation->Margins->children(Gnumeric::NAMESPACE_GNM) as $key => $margin) {
@@ -83,6 +88,7 @@ class PageSetup
         return $marginSet;
     }
 
+    /** @param float[] $marginSet */
     private function adjustMargins(array $marginSet): void
     {
         foreach ($marginSet as $key => $marginSize) {
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric/Styles.php b/src/PhpSpreadsheet/Reader/Gnumeric/Styles.php
index f901c4a9b..9bb664f4d 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric/Styles.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric/Styles.php
@@ -18,6 +18,7 @@ class Styles
 
     protected bool $readDataOnly;
 
+    /** @var array<string, string[]> */
     public static array $mappings = [
         'borderStyle' => [
             '0' => Border::BORDER_NONE,
@@ -100,6 +101,7 @@ class Styles
 
                 $styleAttributes = $style->Style->attributes();
 
+                /** @var mixed[][] */
                 $styleArray = [];
                 // We still set the number format mask for date/time values, even if readDataOnly is true
                 //    so that we can identify whether a float is a float or a date value
@@ -117,6 +119,7 @@ class Styles
         }
     }
 
+    /** @param mixed[][] $styleArray */
     private function addBorderDiagonal(SimpleXMLElement $srssb, array &$styleArray): void
     {
         if (isset($srssb->Diagonal, $srssb->{'Rev-Diagonal'})) {
@@ -131,11 +134,14 @@ class Styles
         }
     }
 
+    /** @param mixed[][] $styleArray */
     private function addBorderStyle(SimpleXMLElement $srssb, array &$styleArray, string $direction): void
     {
         $ucDirection = ucfirst($direction);
         if (isset($srssb->$ucDirection)) {
-            $styleArray['borders'][$direction] = self::parseBorderAttributes($srssb->$ucDirection->attributes());
+            /** @var SimpleXMLElement */
+            $temp = $srssb->$ucDirection;
+            $styleArray['borders'][$direction] = self::parseBorderAttributes($temp->attributes());
         }
     }
 
@@ -150,13 +156,15 @@ class Styles
         return $rotation;
     }
 
+    /** @param mixed[][] $styleArray */
     private static function addStyle(array &$styleArray, string $key, string $value): void
     {
         if (array_key_exists($value, self::$mappings[$key])) {
-            $styleArray[$key] = self::$mappings[$key][$value];
+            $styleArray[$key] = self::$mappings[$key][$value]; //* @phpstan-ignore-line
         }
     }
 
+    /** @param mixed[][] $styleArray */
     private static function addStyle2(array &$styleArray, string $key1, string $key, string $value): void
     {
         if (array_key_exists($value, self::$mappings[$key])) {
@@ -164,8 +172,10 @@ class Styles
         }
     }
 
+    /** @return mixed[][] */
     private static function parseBorderAttributes(?SimpleXMLElement $borderAttributes): array
     {
+        /** @var mixed[][] */
         $styleArray = [];
         if ($borderAttributes !== null) {
             if (isset($borderAttributes['Color'])) {
@@ -174,6 +184,7 @@ class Styles
 
             self::addStyle($styleArray, 'borderStyle', (string) $borderAttributes['Style']);
         }
+        /** @var mixed[][] $styleArray */
 
         return $styleArray;
     }
@@ -188,9 +199,11 @@ class Styles
         return $gnmR . $gnmG . $gnmB;
     }
 
+    /** @param mixed[][] $styleArray */
     private function addColors(array &$styleArray, SimpleXMLElement $styleAttributes): void
     {
         $RGB = self::parseGnumericColour((string) $styleAttributes['Fore']);
+        /** @var mixed[][][] $styleArray */
         $styleArray['font']['color']['rgb'] = $RGB;
         $RGB = self::parseGnumericColour((string) $styleAttributes['Back']);
         $shade = (string) $styleAttributes['Shade'];
@@ -221,6 +234,11 @@ class Styles
         return $cellRange;
     }
 
+    /**
+     * @param mixed[][] $styleArray
+     *
+     * @return mixed[]
+     */
     private function readStyle(array $styleArray, SimpleXMLElement $styleAttributes, SimpleXMLElement $style): array
     {
         self::addStyle2($styleArray, 'alignment', 'horizontal', (string) $styleAttributes['HAlign']);
diff --git a/src/PhpSpreadsheet/Reader/IReader.php b/src/PhpSpreadsheet/Reader/IReader.php
index 250ef4f1c..a003b96fd 100644
--- a/src/PhpSpreadsheet/Reader/IReader.php
+++ b/src/PhpSpreadsheet/Reader/IReader.php
@@ -96,13 +96,15 @@ interface IReader
      * Get which sheets to load
      * Returns either an array of worksheet names (the list of worksheets that should be loaded), or a null
      *        indicating that all worksheets in the workbook should be loaded.
+     *
+     * @return null|string[]
      */
     public function getLoadSheetsOnly(): ?array;
 
     /**
      * Set which sheets to load.
      *
-     * @param null|array|string $value This should be either an array of worksheet names to be loaded,
+     * @param null|string|string[] $value This should be either an array of worksheet names to be loaded,
      *          or a string containing a single worksheet name. If NULL, then it tells the Reader to
      *          read all worksheets in the workbook
      *
diff --git a/src/PhpSpreadsheet/Reader/Ods.php b/src/PhpSpreadsheet/Reader/Ods.php
index 3b8609b0d..420ae2f7b 100644
--- a/src/PhpSpreadsheet/Reader/Ods.php
+++ b/src/PhpSpreadsheet/Reader/Ods.php
@@ -259,6 +259,7 @@ class Ods extends BaseReader
             throw new Exception('Unable to read data from {$pFilename}');
         }
 
+        /** @var array{meta?: string, office?: string, dc?: string} */
         $namespacesMeta = $xml->getNamespaces(true);
 
         (new DocumentProperties($spreadsheet))->load($xml, $namespacesMeta);
@@ -383,6 +384,7 @@ class Ods extends BaseReader
                                 $columnWidth = new HelperDimension($columnWidths[$tableStyleName]);
                                 $tableColumnString = Coordinate::stringFromColumnIndex($tableColumnIndex);
                                 for ($rowRepeats2 = $rowRepeats; $rowRepeats2 > 0; --$rowRepeats2) {
+                                    /** @var string $tableColumnString */
                                     $spreadsheet->getActiveSheet()
                                         ->getColumnDimension($tableColumnString)
                                         ->setWidth($columnWidth->toUnit('cm'), 'cm');
diff --git a/src/PhpSpreadsheet/Reader/Ods/PageSettings.php b/src/PhpSpreadsheet/Reader/Ods/PageSettings.php
index fd35de5b9..26173b6f8 100644
--- a/src/PhpSpreadsheet/Reader/Ods/PageSettings.php
+++ b/src/PhpSpreadsheet/Reader/Ods/PageSettings.php
@@ -5,6 +5,7 @@ namespace PhpOffice\PhpSpreadsheet\Reader\Ods;
 use DOMDocument;
 use PhpOffice\PhpSpreadsheet\Worksheet\PageSetup;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use stdClass;
 
 class PageSettings
 {
@@ -21,6 +22,7 @@ class PageSettings
      */
     private array $tableStylesCrossReference = [];
 
+    /** @var mixed[] */
     private array $pageLayoutStyles = [];
 
     /**
@@ -151,12 +153,15 @@ class PageSettings
         if (!array_key_exists($printSettingsIndex, $this->pageLayoutStyles)) {
             return;
         }
+        /** @var (object{orientation: string, scale: int|string, printOrder: string|null,
+         * horizontalCentered: bool, verticalCentered: bool, marginLeft: float, marginRight: float, marginTop: float,
+         * marginBottom: float, marginHeader: float, marginFooter: float}&stdClass) */
         $printSettings = $this->pageLayoutStyles[$printSettingsIndex];
 
         $worksheet->getPageSetup()
             ->setOrientation($printSettings->orientation ?? PageSetup::ORIENTATION_DEFAULT)
             ->setPageOrder($printSettings->printOrder === 'ltr' ? PageSetup::PAGEORDER_OVER_THEN_DOWN : PageSetup::PAGEORDER_DOWN_THEN_OVER)
-            ->setScale((int) trim($printSettings->scale, '%'))
+            ->setScale((int) trim((string) $printSettings->scale, '%'))
             ->setHorizontalCentered($printSettings->horizontalCentered)
             ->setVerticalCentered($printSettings->verticalCentered);
 
diff --git a/src/PhpSpreadsheet/Reader/Ods/Properties.php b/src/PhpSpreadsheet/Reader/Ods/Properties.php
index a5f0c79f4..4dada28fc 100644
--- a/src/PhpSpreadsheet/Reader/Ods/Properties.php
+++ b/src/PhpSpreadsheet/Reader/Ods/Properties.php
@@ -15,10 +15,11 @@ class Properties
         $this->spreadsheet = $spreadsheet;
     }
 
+    /** @param array{meta?: string, office?: string, dc?: string} $namespacesMeta */
     public function load(SimpleXMLElement $xml, array $namespacesMeta): void
     {
         $docProps = $this->spreadsheet->getProperties();
-        $officeProperty = $xml->children($namespacesMeta['office']);
+        $officeProperty = $xml->children($namespacesMeta['office'] ?? '');
         foreach ($officeProperty as $officePropertyData) {
             if (isset($namespacesMeta['dc'])) {
                 $officePropertiesDC = $officePropertyData->children($namespacesMeta['dc']);
@@ -27,7 +28,7 @@ class Properties
 
             $officePropertyMeta = null;
             if (isset($namespacesMeta['dc'])) {
-                $officePropertyMeta = $officePropertyData->children($namespacesMeta['meta']);
+                $officePropertyMeta = $officePropertyData->children($namespacesMeta['meta'] ?? '');
             }
             $officePropertyMeta = $officePropertyMeta ?? [];
             foreach ($officePropertyMeta as $propertyName => $propertyValue) {
@@ -66,13 +67,14 @@ class Properties
         }
     }
 
+    /** @param array{meta?: string, office?: mixed, dc?: mixed} $namespacesMeta */
     private function setMetaProperties(
         array $namespacesMeta,
         SimpleXMLElement $propertyValue,
         string $propertyName,
         DocumentProperties $docProps
     ): void {
-        $propertyValueAttributes = $propertyValue->attributes($namespacesMeta['meta']);
+        $propertyValueAttributes = $propertyValue->attributes($namespacesMeta['meta'] ?? '');
         $propertyValue = (string) $propertyValue;
         switch ($propertyName) {
             case 'initial-creator':
@@ -101,14 +103,17 @@ class Properties
         }
     }
 
+    /** @param iterable<string> $propertyValueAttributes */
     private function setUserDefinedProperty(iterable $propertyValueAttributes, string $propertyValue, DocumentProperties $docProps): void
     {
         $propertyValueName = '';
         $propertyValueType = DocumentProperties::PROPERTY_TYPE_STRING;
         foreach ($propertyValueAttributes as $key => $value) {
             if ($key == 'name') {
+                /** @var scalar $value */
                 $propertyValueName = (string) $value;
             } elseif ($key == 'value-type') {
+                /** @var string $value */
                 switch ($value) {
                     case 'date':
                         $propertyValue = DocumentProperties::convertProperty($propertyValue, 'date');
diff --git a/src/PhpSpreadsheet/Reader/Security/XmlScanner.php b/src/PhpSpreadsheet/Reader/Security/XmlScanner.php
index 6d4ed449e..e4da44f31 100644
--- a/src/PhpSpreadsheet/Reader/Security/XmlScanner.php
+++ b/src/PhpSpreadsheet/Reader/Security/XmlScanner.php
@@ -102,6 +102,7 @@ class XmlScanner
         if ($this->callback !== null) {
             $xml = call_user_func($this->callback, $xml);
         }
+        /** @var string $xml */
 
         return $xml;
     }
diff --git a/src/PhpSpreadsheet/Reader/Slk.php b/src/PhpSpreadsheet/Reader/Slk.php
index 27b66a0d1..d3d59f0e1 100644
--- a/src/PhpSpreadsheet/Reader/Slk.php
+++ b/src/PhpSpreadsheet/Reader/Slk.php
@@ -21,6 +21,8 @@ class Slk extends BaseReader
 
     /**
      * Formats.
+     *
+     * @var mixed[]
      */
     private array $formats = [];
 
@@ -31,6 +33,8 @@ class Slk extends BaseReader
 
     /**
      * Fonts.
+     *
+     * @var mixed[]
      */
     private array $fonts = [];
 
@@ -94,8 +98,7 @@ class Slk extends BaseReader
         $fileHandle = $this->fileHandle;
         rewind($fileHandle);
 
-        $worksheetInfo = [];
-        $worksheetInfo[0]['worksheetName'] = basename($filename, '.slk');
+        $worksheetInfo = [['worksheetName' => basename($filename, '.slk')]];
 
         // loop through one row (line) at a time in the file
         $rowIndex = 0;
@@ -218,6 +221,7 @@ class Slk extends BaseReader
         $hasCalculatedValue = true;
     }
 
+    /** @param mixed[] $rowData */
     private function processCRecord(array $rowData, Spreadsheet &$spreadsheet, string &$row, string &$column): void
     {
         //    Read cell value data
@@ -227,6 +231,7 @@ class Slk extends BaseReader
         $sharedColumn = $sharedRow = -1;
         $sharedFormula = false;
         foreach ($rowData as $rowDatum) {
+            /** @var string $rowDatum */
             switch ($rowDatum[0]) {
                 case 'X':
                     $column = substr($rowDatum, 1);
@@ -302,6 +307,7 @@ class Slk extends BaseReader
         }
     }
 
+    /** @param mixed[] $rowData */
     private function processFRecord(array $rowData, Spreadsheet &$spreadsheet, string &$row, string &$column): void
     {
         //    Read cell formatting
@@ -310,6 +316,7 @@ class Slk extends BaseReader
         $fontStyle = '';
         $styleData = [];
         foreach ($rowData as $rowDatum) {
+            /** @var string $rowDatum */
             switch ($rowDatum[0]) {
                 case 'C':
                 case 'X':
@@ -335,6 +342,7 @@ class Slk extends BaseReader
                     break;
             }
         }
+        /** @var string $formatStyle */
         $this->addFormats($spreadsheet, $formatStyle, $row, $column);
         $this->addFonts($spreadsheet, $fontStyle, $row, $column);
         $this->addStyle($spreadsheet, $styleData, $row, $column);
@@ -350,6 +358,7 @@ class Slk extends BaseReader
         'T' => 'top',
     ];
 
+    /** @param mixed[][] $styleData */
     private function styleSettings(string $rowDatum, array &$styleData, string &$fontStyle): void
     {
         $styleSettings = substr($rowDatum, 1);
@@ -359,7 +368,7 @@ class Slk extends BaseReader
             if (array_key_exists($char, self::STYLE_SETTINGS_FONT)) {
                 $styleData['font'][self::STYLE_SETTINGS_FONT[$char]] = true;
             } elseif (array_key_exists($char, self::STYLE_SETTINGS_BORDER)) {
-                $styleData['borders'][self::STYLE_SETTINGS_BORDER[$char]]['borderStyle'] = Border::BORDER_THIN;
+                $styleData['borders'][self::STYLE_SETTINGS_BORDER[$char]]['borderStyle'] = Border::BORDER_THIN; //* @phpstan-ignore-line
             } elseif ($char == 'S') {
                 $styleData['fill']['fillType'] = Fill::FILL_PATTERN_GRAY125;
             } elseif ($char == 'M') {
@@ -374,7 +383,7 @@ class Slk extends BaseReader
     {
         if ($formatStyle && $column > '' && $row > '') {
             $columnLetter = Coordinate::stringFromColumnIndex((int) $column);
-            if (isset($this->formats[$formatStyle])) {
+            if (isset($this->formats[$formatStyle]) && is_array($this->formats[$formatStyle])) {
                 $spreadsheet->getActiveSheet()->getStyle($columnLetter . $row)->applyFromArray($this->formats[$formatStyle]);
             }
         }
@@ -384,12 +393,13 @@ class Slk extends BaseReader
     {
         if ($fontStyle && $column > '' && $row > '') {
             $columnLetter = Coordinate::stringFromColumnIndex((int) $column);
-            if (isset($this->fonts[$fontStyle])) {
+            if (isset($this->fonts[$fontStyle]) && is_array($this->fonts[$fontStyle])) {
                 $spreadsheet->getActiveSheet()->getStyle($columnLetter . $row)->applyFromArray($this->fonts[$fontStyle]);
             }
         }
     }
 
+    /** @param mixed[] $styleData */
     private function addStyle(Spreadsheet &$spreadsheet, array $styleData, string $row, string $column): void
     {
         if ((!empty($styleData)) && $column > '' && $row > '') {
@@ -409,13 +419,14 @@ class Slk extends BaseReader
                 $endCol = Coordinate::stringFromColumnIndex((int) $endCol);
                 $spreadsheet->getActiveSheet()->getColumnDimension($startCol)->setWidth((float) $columnWidth);
                 do {
-                    // ++$startCol below tricks Phpstan into thinking it's float/int
+                    /** @var string $startCol */
                     $spreadsheet->getActiveSheet()->getColumnDimension((string) ++$startCol)->setWidth((float) $columnWidth);
-                } while ($startCol !== $endCol); // @phpstan-ignore-line
+                } while ($startCol !== $endCol);
             }
         }
     }
 
+    /** @param string[] $rowData */
     private function processPRecord(array $rowData, Spreadsheet &$spreadsheet): void
     {
         //    Read shared styles
@@ -438,6 +449,7 @@ class Slk extends BaseReader
 
                     break;
                 case 'L':
+                    /** @var mixed[][][] $formatArray */
                     $this->processPColors($rowDatum, $formatArray);
 
                     break;
@@ -450,6 +462,7 @@ class Slk extends BaseReader
         $this->processPFinal($spreadsheet, $formatArray);
     }
 
+    /** @param mixed[][][] $formatArray */
     private function processPColors(string $rowDatum, array &$formatArray): void
     {
         if (preg_match('/L([1-9]\d*)/', $rowDatum, $matches)) {
@@ -458,6 +471,7 @@ class Slk extends BaseReader
         }
     }
 
+    /** @param mixed[][] $formatArray */
     private function processPFontStyles(string $rowDatum, array &$formatArray): void
     {
         $styleSettings = substr($rowDatum, 1);
@@ -469,6 +483,7 @@ class Slk extends BaseReader
         }
     }
 
+    /** @param mixed[] $formatArray */
     private function processPFinal(Spreadsheet &$spreadsheet, array $formatArray): void
     {
         if (array_key_exists('numberFormat', $formatArray)) {
@@ -534,6 +549,7 @@ class Slk extends BaseReader
         return $spreadsheet;
     }
 
+    /** @param string[] $rowData */
     private function columnRowFromRowData(array $rowData, string &$column, string &$row): void
     {
         foreach ($rowData as $rowDatum) {
diff --git a/src/PhpSpreadsheet/Reader/Xml.php b/src/PhpSpreadsheet/Reader/Xml.php
index 95715a632..9c2cf205f 100644
--- a/src/PhpSpreadsheet/Reader/Xml.php
+++ b/src/PhpSpreadsheet/Reader/Xml.php
@@ -32,6 +32,8 @@ class Xml extends BaseReader
 
     /**
      * Formats.
+     *
+     * @var mixed[]
      */
     protected array $styles = [];
 
@@ -60,6 +62,7 @@ class Xml extends BaseReader
 
     private string $xmlFailMessage = '';
 
+    /** @return mixed[] */
     public static function xmlMappings(): array
     {
         return array_merge(
@@ -145,6 +148,8 @@ class Xml extends BaseReader
 
     /**
      * Reads names of the worksheets from a file, without parsing the whole file to a Spreadsheet object.
+     *
+     * @return string[]
      */
     public function listWorksheetNames(string $filename): array
     {
@@ -294,7 +299,7 @@ class Xml extends BaseReader
         (new Properties($spreadsheet))->readProperties($xml, $namespaces);
 
         $this->styles = (new Style())->parseStyles($xml, $namespaces);
-        if (isset($this->styles['Default'])) {
+        if (isset($this->styles['Default']) && is_array($this->styles['Default'])) {
             $spreadsheet->getCellXfCollection()[0]->applyFromArray($this->styles['Default']);
         }
 
@@ -366,6 +371,7 @@ class Xml extends BaseReader
                         $columnVisible = ((string) $columnData_ss['Hidden']) !== '1';
                     }
                     while ($colspan >= 0) {
+                        /** @var string $columnID */
                         if (isset($columnWidth)) {
                             $spreadsheet->getActiveSheet()->getColumnDimension($columnID)->setWidth($columnWidth / 5.4);
                         }
@@ -514,11 +520,12 @@ class Xml extends BaseReader
 
                         if (isset($cell_ss['StyleID'])) {
                             $style = (string) $cell_ss['StyleID'];
-                            if ((isset($this->styles[$style])) && (!empty($this->styles[$style]))) {
+                            if ((isset($this->styles[$style])) && is_array($this->styles[$style]) && (!empty($this->styles[$style]))) {
                                 $spreadsheet->getActiveSheet()->getStyle($cellRange)
                                     ->applyFromArray($this->styles[$style]);
                             }
                         }
+                        /** @var string $columnID */
                         ++$columnID;
                         while ($additionalMergedCells > 0) {
                             ++$columnID;
diff --git a/src/PhpSpreadsheet/Reader/Xml/DataValidations.php b/src/PhpSpreadsheet/Reader/Xml/DataValidations.php
index faa2fb2c2..74d7ec46a 100644
--- a/src/PhpSpreadsheet/Reader/Xml/DataValidations.php
+++ b/src/PhpSpreadsheet/Reader/Xml/DataValidations.php
@@ -30,6 +30,7 @@ class DataValidations
 
     private int $thisColumn = 0;
 
+    /** @param string[] $matches */
     private function replaceR1C1(array $matches): string
     {
         return AddressHelper::convertToA1($matches[0], $this->thisRow, $this->thisColumn, false);
diff --git a/src/PhpSpreadsheet/Reader/Xml/PageSettings.php b/src/PhpSpreadsheet/Reader/Xml/PageSettings.php
index 8f9d4645d..e185db8e5 100644
--- a/src/PhpSpreadsheet/Reader/Xml/PageSettings.php
+++ b/src/PhpSpreadsheet/Reader/Xml/PageSettings.php
@@ -10,12 +10,16 @@ use stdClass;
 
 class PageSettings
 {
+    /** @var (object{orientation: string, scale: ?int, printOrder: string|null,
+     * paperSize: int,
+     * horizontalCentered: bool, verticalCentered: bool, leftMargin: float, rightMargin: float, topMargin: float,
+     * bottomMargin: float, headerMargin: float, footerMargin: float}&stdClass) */
     private stdClass $printSettings;
 
     public function __construct(SimpleXMLElement $xmlX)
     {
         $printSettings = $this->pageSetup($xmlX, $this->getPrintDefaults());
-        $this->printSettings = $this->printSetup($xmlX, $printSettings);
+        $this->printSettings = $this->printSetup($xmlX, $printSettings); //* @phpstan-ignore-line
     }
 
     public function loadPageSettings(Spreadsheet $spreadsheet): void
diff --git a/src/PhpSpreadsheet/Reader/Xml/Properties.php b/src/PhpSpreadsheet/Reader/Xml/Properties.php
index 17e112130..83116baec 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Properties.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Properties.php
@@ -15,6 +15,7 @@ class Properties
         $this->spreadsheet = $spreadsheet;
     }
 
+    /** @param string[] $namespaces */
     public function readProperties(SimpleXMLElement $xml, array $namespaces): void
     {
         $this->readStandardProperties($xml);
@@ -34,6 +35,7 @@ class Properties
         }
     }
 
+    /** @param string[] $namespaces */
     protected function readCustomProperties(SimpleXMLElement $xml, array $namespaces): void
     {
         if (isset($xml->CustomDocumentProperties) && is_iterable($xml->CustomDocumentProperties[0])) {
@@ -143,6 +145,7 @@ class Properties
         $docProps->setCustomProperty($propertyName, $propertyValue, $propertyType);
     }
 
+    /** @param string[] $hex */
     protected function hex2str(array $hex): string
     {
         return mb_chr((int) hexdec($hex[1]), 'UTF-8');
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style.php b/src/PhpSpreadsheet/Reader/Xml/Style.php
index c6b514944..faf706165 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style.php
@@ -9,9 +9,16 @@ class Style
 {
     /**
      * Formats.
+     *
+     * @var mixed[]
      */
     protected array $styles = [];
 
+    /**
+     * @param string[] $namespaces
+     *
+     * @return mixed[]
+     */
     public function parseStyles(SimpleXMLElement $xml, array $namespaces): array
     {
         $children = $xml->children('urn:schemas-microsoft-com:office:spreadsheet');
@@ -27,6 +34,7 @@ class Style
         $numberFormatStyleParser = new Style\NumberFormat();
 
         foreach ($stylesXml as $style) {
+            /** @var SimpleXMLElement $style */
             $style_ss = self::getAttributes($style, $namespaces['ss']);
             $styleID = (string) $style_ss['ID'];
             $this->styles[$styleID] = $this->styles['Default'] ?? [];
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/Alignment.php b/src/PhpSpreadsheet/Reader/Xml/Style/Alignment.php
index 7bbda1348..657decfff 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/Alignment.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/Alignment.php
@@ -23,6 +23,7 @@ class Alignment extends StyleBase
         AlignmentStyles::HORIZONTAL_JUSTIFY,
     ];
 
+    /** @return mixed[] */
     public function parseStyle(SimpleXMLElement $styleAttributes): array
     {
         $style = [];
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/Border.php b/src/PhpSpreadsheet/Reader/Xml/Style/Border.php
index dfde17ae3..349eaab60 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/Border.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/Border.php
@@ -15,9 +15,6 @@ class Border extends StyleBase
         'right',
     ];
 
-    /**
-     * @var array
-     */
     public const BORDER_MAPPINGS = [
         'borderStyle' => [
             'continuous' => BorderStyle::BORDER_HAIR,
@@ -53,6 +50,11 @@ class Border extends StyleBase
         ],
     ];
 
+    /**
+     * @param string[] $namespaces
+     *
+     * @return mixed[]
+     */
     public function parseStyle(SimpleXMLElement $styleData, array $namespaces): array
     {
         $style = [];
@@ -70,6 +72,7 @@ class Border extends StyleBase
                 $borderStyleValue = (string) $borderStyleValuex;
                 switch ($borderStyleKey) {
                     case 'Position':
+                        /** @var string $diagonalDirection */
                         [$borderPosition, $diagonalDirection]
                             = $this->parsePosition($borderStyleValue, $diagonalDirection);
 
@@ -93,6 +96,7 @@ class Border extends StyleBase
         return $style;
     }
 
+    /** @return mixed[] */
     protected function parsePosition(string $borderStyleValue, string $diagonalDirection): array
     {
         $borderStyleValue = strtolower($borderStyleValue);
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/Fill.php b/src/PhpSpreadsheet/Reader/Xml/Style/Fill.php
index 9a6121525..8dc723205 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/Fill.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/Fill.php
@@ -7,9 +7,6 @@ use SimpleXMLElement;
 
 class Fill extends StyleBase
 {
-    /**
-     * @var array
-     */
     public const FILL_MAPPINGS = [
         'fillType' => [
             'solid' => FillStyles::FILL_SOLID,
@@ -33,6 +30,7 @@ class Fill extends StyleBase
         ],
     ];
 
+    /** @return mixed[] */
     public function parseStyle(SimpleXMLElement $styleAttributes): array
     {
         $style = [];
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/Font.php b/src/PhpSpreadsheet/Reader/Xml/Style/Font.php
index 5f824889a..4a5243a68 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/Font.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/Font.php
@@ -15,6 +15,11 @@ class Font extends StyleBase
         FontUnderline::UNDERLINE_SINGLEACCOUNTING,
     ];
 
+    /**
+     * @param mixed[][] $style
+     *
+     * @return mixed[][]
+     */
     protected function parseUnderline(array $style, string $styleAttributeValue): array
     {
         if (self::identifyFixedStyleValue(self::UNDERLINE_STYLES, $styleAttributeValue)) {
@@ -24,6 +29,11 @@ class Font extends StyleBase
         return $style;
     }
 
+    /**
+     * @param mixed[][] $style
+     *
+     * @return mixed[][]
+     */
     protected function parseVerticalAlign(array $style, string $styleAttributeValue): array
     {
         if ($styleAttributeValue == 'Superscript') {
@@ -36,6 +46,7 @@ class Font extends StyleBase
         return $style;
     }
 
+    /** @return mixed[] */
     public function parseStyle(SimpleXMLElement $styleAttributes): array
     {
         $style = [];
@@ -52,6 +63,7 @@ class Font extends StyleBase
 
                     break;
                 case 'Color':
+                    /** @var string[][][] $style */
                     $style['font']['color']['rgb'] = substr($styleAttributeValue, 1);
 
                     break;
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/NumberFormat.php b/src/PhpSpreadsheet/Reader/Xml/Style/NumberFormat.php
index a31aa9ebd..e6fffe176 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/NumberFormat.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/NumberFormat.php
@@ -6,6 +6,7 @@ use SimpleXMLElement;
 
 class NumberFormat extends StyleBase
 {
+    /** @return mixed[] */
     public function parseStyle(SimpleXMLElement $styleAttributes): array
     {
         $style = [];
diff --git a/src/PhpSpreadsheet/Reader/Xml/Style/StyleBase.php b/src/PhpSpreadsheet/Reader/Xml/Style/StyleBase.php
index 8103a71cb..4217caedd 100644
--- a/src/PhpSpreadsheet/Reader/Xml/Style/StyleBase.php
+++ b/src/PhpSpreadsheet/Reader/Xml/Style/StyleBase.php
@@ -6,6 +6,7 @@ use SimpleXMLElement;
 
 abstract class StyleBase
 {
+    /** @param string[] $styleList */
     protected static function identifyFixedStyleValue(array $styleList, string &$styleAttributeValue): bool
     {
         $returnValue = false;
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormula2Test.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormula2Test.php
index bf45461c8..fe5244fe1 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormula2Test.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormula2Test.php
@@ -5,11 +5,13 @@ namespace PhpOffice\PhpSpreadsheetTests\Reader\Gnumeric;
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
 use PhpOffice\PhpSpreadsheet\Cell\DataType;
 use PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 
 class ArrayFormula2Test extends TestCase
 {
-    #[\PHPUnit\Framework\Attributes\DataProvider('arrayFormulaReaderProvider')]
+    /** @param mixed[] $expectedValue */
+    #[DataProvider('arrayFormulaReaderProvider')]
     public function testArrayFormulaReader(
         string $cellAddress,
         string $expectedRange,
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormulaTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormulaTest.php
index 2943ebead..20ad850df 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormulaTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/ArrayFormulaTest.php
@@ -5,11 +5,13 @@ namespace PhpOffice\PhpSpreadsheetTests\Reader\Gnumeric;
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
 use PhpOffice\PhpSpreadsheet\Cell\DataType;
 use PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 
 class ArrayFormulaTest extends TestCase
 {
-    #[\PHPUnit\Framework\Attributes\DataProvider('arrayFormulaReaderProvider')]
+    /** @param float|mixed[] $expectedValue */
+    #[DataProvider('arrayFormulaReaderProvider')]
     public function testArrayFormulaReader(
         string $cellAddress,
         string $expectedRange,
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericStylesTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericStylesTest.php
index dfb046f51..429a2ee86 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericStylesTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/GnumericStylesTest.php
@@ -10,14 +10,16 @@ use PhpOffice\PhpSpreadsheet\Style\Alignment;
 use PhpOffice\PhpSpreadsheet\Style\Border;
 use PhpOffice\PhpSpreadsheet\Style\Fill;
 use PhpOffice\PhpSpreadsheet\Style\Font;
+use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 
 class GnumericStylesTest extends TestCase
 {
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerBorderStyle')]
+    #[DataProvider('providerBorderStyle')]
     public function testBorderStyle(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var string[] */
         $borders = $styles['borderStyle'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -25,11 +27,13 @@ class GnumericStylesTest extends TestCase
     public function testBorderStyleCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['borderStyle'];
         $covered = [];
         foreach ($expected as $key => $val) {
             $covered[$key] = 0;
         }
+        /** @var mixed[][] */
         $tests = $this->providerBorderStyle();
         foreach ($tests as $test) {
             $covered[$test[0]] = 1;
@@ -39,10 +43,11 @@ class GnumericStylesTest extends TestCase
         }
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerfillType')]
+    #[DataProvider('providerfillType')]
     public function testFillType(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var string[] */
         $borders = $styles['fillType'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -50,6 +55,7 @@ class GnumericStylesTest extends TestCase
     public function testFillTypeCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['fillType'];
         $covered = [];
         foreach ($expected as $key => $val) {
@@ -64,10 +70,11 @@ class GnumericStylesTest extends TestCase
         }
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerHorizontal')]
+    #[DataProvider('providerHorizontal')]
     public function testHorizontal(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var string[] */
         $borders = $styles['horizontal'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -75,11 +82,13 @@ class GnumericStylesTest extends TestCase
     public function testHorizontalCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['horizontal'];
         $covered = [];
         foreach ($expected as $key => $val) {
             $covered[$key] = 0;
         }
+        /** @var mixed[][] */
         $tests = $this->providerHorizontal();
         foreach ($tests as $test) {
             $covered[$test[0]] = 1;
@@ -89,10 +98,11 @@ class GnumericStylesTest extends TestCase
         }
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerunderline')]
+    #[DataProvider('providerunderline')]
     public function testUnderline(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var string[] */
         $borders = $styles['underline'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -100,11 +110,14 @@ class GnumericStylesTest extends TestCase
     public function testUnderlineCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['underline'];
+        /** @var int[] $covered */
         $covered = [];
         foreach ($expected as $key => $val) {
             $covered[$key] = 0;
         }
+        /** @var mixed[][] */
         $tests = $this->providerUnderline();
         foreach ($tests as $test) {
             $covered[$test[0]] = 1;
@@ -114,10 +127,11 @@ class GnumericStylesTest extends TestCase
         }
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerVertical')]
+    #[DataProvider('providerVertical')]
     public function testVertical(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $borders = $styles['vertical'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -125,11 +139,13 @@ class GnumericStylesTest extends TestCase
     public function testVerticalCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['vertical'];
         $covered = [];
         foreach ($expected as $key => $val) {
             $covered[$key] = 0;
         }
+        /** @var int[][] */
         $tests = $this->providerVertical();
         foreach ($tests as $test) {
             $covered[$test[0]] = 1;
@@ -139,10 +155,11 @@ class GnumericStylesTest extends TestCase
         }
     }
 
-    #[\PHPUnit\Framework\Attributes\DataProvider('providerDataType')]
+    #[DataProvider('providerDataType')]
     public function testDataType(string $style, string $expectedResult): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var string[] */
         $borders = $styles['dataType'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -150,6 +167,7 @@ class GnumericStylesTest extends TestCase
     public function testDataTypeCoverage(): void
     {
         $styles = Gnumeric::gnumericMappings();
+        /** @var mixed[] */
         $expected = $styles['dataType'];
         self::assertArrayNotHasKey('70', $expected);
         self::assertArrayNotHasKey('80', $expected);
@@ -157,6 +175,7 @@ class GnumericStylesTest extends TestCase
         foreach ($expected as $key => $val) {
             $covered[$key] = 0;
         }
+        /** @var int[][] */
         $tests = $this->providerDataType();
         foreach ($tests as $test) {
             $covered[$test[0]] = 1;
@@ -186,6 +205,7 @@ class GnumericStylesTest extends TestCase
         ];
     }
 
+    /** @return string[][] */
     public static function providerFillType(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/HiddenWorksheetTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/HiddenWorksheetTest.php
index 92459adce..b6fceb550 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/HiddenWorksheetTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/HiddenWorksheetTest.php
@@ -38,6 +38,7 @@ class HiddenWorksheetTest extends TestCase
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, string[]> */
     private function worksheetAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
index 80002f3c7..d3da858e4 100644
--- a/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Gnumeric/PageSetupTest.php
@@ -79,6 +79,7 @@ class PageSetupTest extends TestCase
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, mixed[]> */
     private function pageSetupAssertions(): array
     {
         return [
@@ -114,6 +115,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
+    /** @return array<string, float[]> */
     private function pageMarginAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/ArrayFormulaTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/ArrayFormulaTest.php
index ab8748540..d6542ac6b 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/ArrayFormulaTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/ArrayFormulaTest.php
@@ -10,6 +10,7 @@ use PHPUnit\Framework\TestCase;
 
 class ArrayFormulaTest extends TestCase
 {
+    /** @param float|mixed[] $expectedValue */
     #[DataProvider('arrayFormulaReaderProvider')]
     public function testArrayFormulaReader(
         string $cellAddress,
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
index 988947f0e..b52f73520 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/HiddenWorksheetTest.php
@@ -38,6 +38,7 @@ class HiddenWorksheetTest extends TestCase
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, array<string, string>> */
     private function worksheetAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupBug1772Test.php b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupBug1772Test.php
index 568bb602c..7e90eea6d 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupBug1772Test.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupBug1772Test.php
@@ -71,6 +71,7 @@ class PageSetupBug1772Test extends TestCase
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, array<string, mixed>> */
     private function pageSetupAssertions(): array
     {
         return [
@@ -84,6 +85,7 @@ class PageSetupBug1772Test extends TestCase
         ];
     }
 
+    /** @return array<string, array<string, float>> */
     private function pageMarginAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
index 227a11c6e..e8e0b59d7 100644
--- a/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Ods/PageSetupTest.php
@@ -73,6 +73,7 @@ class PageSetupTest extends TestCase
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, array<string, mixed>> */
     private function pageSetupAssertions(): array
     {
         return [
@@ -108,6 +109,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
+    /** @return array<string, array<string, float>> */
     private function pageMarginAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xml/DataValidationsTest.php b/tests/PhpSpreadsheetTests/Reader/Xml/DataValidationsTest.php
index 8bbba22d0..5b4d9f17e 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xml/DataValidationsTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xml/DataValidationsTest.php
@@ -99,6 +99,7 @@ class DataValidationsTest extends AbstractFunctional
         $spreadsheet->disconnectWorksheets();
     }
 
+    /** @return array<string, array{bool, string, mixed}> */
     private function validationAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php b/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
index 63e64709f..f0c4dd71f 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xml/PageSetupTest.php
@@ -82,6 +82,7 @@ class PageSetupTest extends TestCase
         self::assertCount($sheetCount, $assertions);
     }
 
+    /** @return array<string, array{orientation: string, scale: int, horizontalCentered: bool, verticalCentered: bool, pageOrder: string}> */
     private function pageSetupAssertions(): array
     {
         return [
@@ -117,6 +118,7 @@ class PageSetupTest extends TestCase
         ];
     }
 
+    /** @return array<string, float[]> */
     private function pageMarginAssertions(): array
     {
         return [
diff --git a/tests/PhpSpreadsheetTests/Reader/Xml/XmlStyleCoverageTest.php b/tests/PhpSpreadsheetTests/Reader/Xml/XmlStyleCoverageTest.php
index 1aa95cfd1..9ddfc8fa2 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xml/XmlStyleCoverageTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xml/XmlStyleCoverageTest.php
@@ -15,6 +15,7 @@ class XmlStyleCoverageTest extends TestCase
     public function testBorderStyle(string $style, string $expectedResult): void
     {
         $styles = Xml::XmlMappings();
+        /** @var string[] */
         $borders = $styles['borderStyle'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -22,6 +23,7 @@ class XmlStyleCoverageTest extends TestCase
     public function testBorderStyleCoverage(): void
     {
         $styles = Xml::XmlMappings();
+        /** @var mixed[] */
         $expected = $styles['borderStyle'];
         $covered = [];
         foreach ($expected as $key => $val) {
@@ -29,6 +31,7 @@ class XmlStyleCoverageTest extends TestCase
         }
         $tests = $this->providerBorderStyle();
         foreach ($tests as $test) {
+            /** @var string[] $test */
             $covered[$test[0]] = 1;
         }
         foreach ($covered as $key => $val) {
@@ -40,6 +43,7 @@ class XmlStyleCoverageTest extends TestCase
     public function testFillType(string $style, string $expectedResult): void
     {
         $styles = Xml::xmlMappings();
+        /** @var string[] */
         $borders = $styles['fillType'];
         self::assertEquals($expectedResult, $borders[$style]);
     }
@@ -47,6 +51,7 @@ class XmlStyleCoverageTest extends TestCase
     public function testFillTypeCoverage(): void
     {
         $styles = Xml::XmlMappings();
+        /** @var string[] */
         $expected = $styles['fillType'];
         $covered = [];
         foreach ($expected as $key => $val) {
@@ -54,6 +59,7 @@ class XmlStyleCoverageTest extends TestCase
         }
         $tests = $this->providerfillType();
         foreach ($tests as $test) {
+            /** @var string[] $test */
             $covered[$test[0]] = 1;
         }
         foreach ($covered as $key => $val) {