As a regular user who across got used to editing css/js subpages for storing non-css/js content across the years, I want to be able to use/edit them again without worries, e.g. without wondering what CSS/JS even is or should be and without receiving a warning I don't undestand.
Cf. https://meta.wikimedia.org/wiki/GlobalCssJs for a more limited case; cf. "MediaWiki should allow creation of empty pages" bug, which I can't find due to T85303/T1375 and T76942+T85302.
For a start, a bot could comment out all the content in EditCounterOptIn.js subpags.
>>! In T76204#800953, @TTO wrote:
> I generated a list of all user JS subpages on the entire WMF cluster (all 222592 of them) and checked the first 20000 (from aawiki down to commonswiki) to see if they contain valid JavaScript.
>
> Valid: 18300
> Invalid: 1189
> Failed: 511 [my script choked on be-x-old, cbk-zam, etc]
> Total: 20000
>
> See P117 for full output.
>
> That's at least 6% containing invalid content, which is a significant proportion. Many of these are `#REDIRECT` pages, caused by T36930 and its see-alsos.
>
> I came across a significant "abuse" of user JS pages: opt-in to the xtools edit counter e.g. [[ast:User:Savh/EditCounterOptIn.js]], [[az:User:Araz Yaquboglu/EditCounterOptIn.js]].