Seen in this build (warning: will slow your browser; unformatted link to curl pipe into less -R) for this Math change; doesn’t seem related to the change.
There were 34 failures:
1) MediaWiki\Extension\DiscussionTools\Tests\CommentFormatterTest::testAddDiscussionToolsInternal with data set #0 ('plwiki oldparser', 'Wikipedia:Kawiarenka/Artykuły...iernik', 'cases/pl-big-oldparser/pl-big...r.html', 'cases/pl-big-oldparser/pl-big...p.html', '../data/plwiki-config.json', '../data/plwiki-data.json', false, true)
plwiki oldparser
Failed asserting that two strings are equal.
(snip VERY long HTML diff)Could be due to Media: Fallback to the largest standard size if an overly large one is requested which was just merged in core?