It's really easy to realise T407974 when investigating this bug, so I'd prefer not to make this public until T407974 is fixed as well.

As that message is loaded by JavaScript, it shouldn't use interwiki links (all interwikis are non-local by default). It should be changed to a normal external link.

In T418683#11661091, @Dragoniez wrote:

In what circumstances did this happen? The interwiki link actually works even on non-WMF wikis like Miraheze.

Sorry for the misleading URL. The English Wikipedia link was made up - I only tested it on some wikis that didn't customize the message like zhwiki and meta.
Yes, in the message source code, it used [[mw:Special:MyLanguage/Help:Temporary_accounts|XXX]]. The issue is that, given that wikitext, it's parsed as the wrong link (/wiki/Mw:...) when it is actually shown in the tooltip.

Sorry, I just noticed that this issue has already been mentioned in T294950. It might still be good to keep this as a subtask for tracking purposes.

The issue mentioned does not actually exist.

I have no idea what this task is requesting for. For a line like for _,v in ipairs(t) do print(v) end, you are actually declare two local variables _ and v, and strict won't raise an error. If you get an error for using global underscore variable, there should be something wrong in your code.

I believe it's related to https://issues.chromium.org/issues/40889720, in which Chrome doesn't support the columnalign attribute at all.