You can find the ID of those strings by attaching uselang=qqx to the URL.

• The help link at the top right corner of the recent change list

https://www.mediawiki.org/wiki/Special:RecentChanges?uselang=qqx says that is helppage-top-gethelp

• The same help link for the Special:AllPages page itself

I do not see any such help link: https://www.mediawiki.org/wiki/Special:AllPages?uselang=qqx

So this seems to be about helppage-top-gethelp not being listed in Special:AllMessages?
I cannot quickly reproduce as https://www.mediawiki.org/w/index.php?title=Special:AllMessages&offset=Helppage lists the entry, and it can be translated via https://translatewiki.net/w/i.php?title=Special%3ASearchTranslations&group=mediawiki&grouppath=mediawiki&query=language%3Aen^25+messageid%3A%22MediaWiki%3AHelppage-top-gethelp%22^10+%22Help%22tqqx

But I did not check the content of the MediaWiki Language Extension Bundle, which version of that bundle do you use exactly?

So this is documented in a meta page that was rejected to go in mediawiki.org. Weird. I was just looking for the "meta.wikimedia" string in the list - the search feature in Special:AllMessages isn't exactly helpful as it only allows to search for string IDs. Though in this case even being able to search into arguments would fail.

TBH I don't even know that the Language Extension Bundle is, I just presumed it was the right component. My bad, sorry.

Feel free to mark this one as INVALID or whatever the equivalent is for Phabricator. Thanks for your input.

On second thoughts, helppage-top-gethelp is only a label, so I still can't make the link point elsewhere, e.g. a local help page. So the feature request is still valid...

In T135972#2318597, @Aklapper wrote:

In T135972#2317532, @tactica wrote:

So this is documented in a meta page that was rejected to go in mediawiki.org.

Can you elaborate? Which meta page? Where was someone "rejected"?

I meant https://meta.wikimedia.org/wiki/Help:System_message which one of the help links is point to by default. There's a blurb there about the page having been rejected from being merged into mediawiki.org, but that's moot now, the ?uselang=qqx trick helped and there's an equivalent page in mediawiki.org already.

What I don't get is why one has to use this trick - the strings should be listed in Special:AllMessages just like everything else.

On second thoughts, helppage-top-gethelp is only a label, so I still can't make the link point elsewhere, e.g. a local help page.

You can. See https://phabricator.wikimedia.org/diffusion/MW/browse/master/includes/OutputPage.php;bd2c495b99ac0f95a323a55b0edb4c172a289a25$1398

Indeed, this explained a lot. Thank you for your patience :)

In T135972#2319112, @tactica wrote:

In T135972#2318597, @Aklapper wrote:

In T135972#2317532, @tactica wrote:

So this is documented in a meta page that was rejected to go in mediawiki.org.

Can you elaborate? Which meta page? Where was someone "rejected"?

I meant https://meta.wikimedia.org/wiki/Help:System_message which one of the help links is point to by default. There's a blurb there about the page having been rejected from being merged into mediawiki.org

https://meta.wikimedia.org/wiki/Help:System_message is a Help page about system messages (and part of the handbook), and someone decided that it should stay on meta instead of mediawiki.org.
It is not a page about system messages for Help buttons. :)