happy.melon.wiki wrote:

I don't think this should block 1.18 deployment, although it should probably block the tarball. It's not a regression to not provide the entirety of the required replacement :D these features can probably be implemented with just a few lines of JS in Common.js; for sure that's not ideal and should not be a permanent feature, but it's also not going to make the wiki fall over and die to have to keep some JS in play for a while longer. Migrating everything to use "mw-collapsible" rather than just "collapsible" is going to take months, anyway.

Aside from Happy-melon's comment, I'd like to note that it's not a regression or a lacking feature compared to a deprecated or legacy feature.

There has been no previous collapsing script in MediaWiki core, this is the first. There have been many in extensions and dozens of implementations on wikis's site scripts and gadgets. But one can't expect the core plugin to do everything exactly like and featuring every option all other implementations have come up with.

Removing milestone blocker

I left a comment at T72762#2050894 regarding autocollapse.

I see the use case for inner/outercollapse, per the Help page linked in the original ticket but am not sure I've seen its use in the wild (even though an insource search on en.wp clearly indicates that people think they're using it).

I think this should be declined, and the wikis that require it should use the snippet from T72762#2184045 to extend the capabilities of collapsible boxes. This really feels like a very niche feature and an annoyance to support together with all the options that jquery.makeCollapsible already has.