Requested feature overview description.
Provide some way to indicate to users that an alias, implication, or BUR was rejected as part of a mass rejection, and not for some other reason.
Why would it be useful?
It would help users understand if an AIBUR was rejected "on the merits", and therefore probably shouldn't be re-proposed as is, or if it was rejected as part of a mass rejection, and therefore might be worth bringing up again for further discussion.
There are occasional "why was this rejected?" forum threads asking why a particular request was rejected. I think these have become slightly more common since the January 2024 mass rejection.
The mechanism is probably that some user wants to propose a similar AIBUR, does a search, and finds a forum thread about it. If the rejection wasn't due to a mass rejection, there are usually enough "this is a bad idea" or "alias it to this other tag instead" posts in that thread to help the user understand it. But if there was little to no discussion, and then a rejection, the user is confused as to why.
Hopefully, the AIBUR queue won't get so long that mass rejections are needed again. But if it does, this might help prevent user confusion.
Implementation
I can think of at least a couple of ways to do this. One would probably involve a code change, and the other wouldn't.
For both ways, it's probably a good idea to write (and then lock) a wiki page that explains the mass rejection, so users can be referred to that page.
Code change:
Add a "reason" field to AIBUR approvals and rejections, similar to the "reason" field that takedowns have. For mass rejections, this gets set to something like "March 2038 mass rejection - see wiki" (with link to wiki page). This should normally be visible to all users, not just admins.
When doing a mass rejection, I don't know if the admins can do "select all" and reject dozens of requests with one click, or if they use some kind of browser script to automate it, or if they do them one at a time. If there's a "select all" or a browser script, there should be a way for the "reason" to persist, so they don't have to paste it into every single rejection.
No code change:
When a mass rejection is deemed necessary, create a new user named something like "MassRejectionMarch2038". Give this user the required privileges to reject AIBURs. Put a short explanation on that user's profile page, with a link to the wiki page. Then, one of the admins logs in as that new user and does the mass rejection. Afterwards, maybe change that user's status to a normal user, or "former staff", or similar.
That way, users will see something like The tag implication some_tag -> other_tag (forum #524288) has been rejected by @MassRejectionMarch2038 in the forum thread, which will hopefully give them a clue about the rejection reason.
What part(s) of the site page(s) are affected?
For the code-change version, whatever page the admins use to approve or reject AIBURs would need a new input box for "reason".
The pages for each individual AIBUR would need to display this reason (the /tag_alias/nnn, tag_implications/nnn, and /bulk_update_requests/nnn URLs) .
It would be good if the "reason" is also copied into the forum post that's generated when an admin rejects an AIBUR.
