Because of PHP 8.2 deprecation, in f14428e4c0, we stopped converting non-ASCII characters to HTML entities. Instead, we started to explicitly insert `meta[charset]` tag at the start of the document.
Later, we discovered that was breaking `html[lang]` so, in efbbc86df9, we made the insertion smarter. One of the improvements was that it would not insert the `meta[charset]` tag when it was already present.
That, however, broke websites that had `title` tag before `meta[charset]`. On those, libxml2 would decode the `title` contents as ISO-8859-1.
We could improve the logic (e.g. check that there is not text content before `meta[charset]`) or insert the tag unconditionally but it will probably be simplest to just go back to converting the non-ASCII characters to entities, just using non-deprecated function variant.