Same issue here: https://commons.wikimedia.org/wiki/File:SporadicGroups.svg

Is this now an obsolete duplicate of T346291?

I recognize that it might not be obvious from the outside that the current consensus for this task is more like "everyone who even cares would be surprised that this is not yet done". So, here is the discussion, showing overwhelming, unilateral support: https://ru.wikipedia.org/wiki/Википедия:Форум/Правила#Права_флага_арбитра

If we discuss usage, here are my two pennies. In ruwiki, interactive Lua-based graphs are used in more than 26000 articles about settlements and administrative units through https://ru.wikipedia.org/wiki/Module:Statistical (also, more than 8000 on ukwiki, etc.). The Vega template is already rewritten for Vega 5 and can be extracted easily, but the data is processed dynamically, and it is quite hard to change that (although hopefully possible, in principle). Interactivity is highly desirable.

О. В рамках этого проекта будет решена давняя проблема, что сообщение о статусе статьи (ДС/ХС/ИС) отображается в мобильной версии как "Проблемы с подразделом"?

Apparently this is now resolved.

A few occurrences of <ce> are currently present at various wikis. The existence of this task probably implied turning off <ce> at some point, possibly within T153606, but it didn't happen (yet?).

Nope, same as without "unhide=1".

I cannot see blocks on Special:Contributions. I am viewing Special:Log/block. The "show" link goes to Special:RevisionDelete: https://ru.wikipedia.org/w/index.php?title=Special:RevisionDelete&target=Special%3ALog%2Fblock&type=logging&ids=33182256 (the actual link has localized names for the namespaces and the RevisionDelete page) So yes, it seems that it is the same as "change visibility" but with different supposed outcome.
If I manually replace RevisionDelete by Undelete in the URL (by the analogy with the URLs for viewing the deleted revisions, see below), I get an even more cryptic error message: "Permission error. You do not have permission to view a page's deleted history, for the following reason: The action you have requested is limited to users in one of the groups: Administrators, Arbitration committee members." (Note that actually I am an Arbitration committee member.)