Custom properties would be better in this context using j (no leading 0) rather than d (leading 0) for day of month.
Properties has the same problem, and also needs backslashes before p to make it part of a <sup> tag.
A continuation of PR #3859. Change code that would be flagged if we were to run Phpstan at level 9 (we currently run level 8). I may or may not follow up with source code (454 level-9 problems remain for src), but there is no reason to avoid the effort for samples.
No changes are made to src.
oleibman
Adrien Crivelli