See example at https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Special:Log&page=T242823

03:44, 15 January 2020 DannyS712 talk contribs block changed visibility of a revision on page T242823: content hidden, edit summary hidden and username hidden (Demo T242823) (diff | more...)
03:44, 15 January 2020 DannyS712 talk contribs block deleted page T242823 (Delete) (view/restore)
03:43, 15 January 2020 DannyS712 talk contribs block created page T242823 (create)

Couldn't this still be warranted? Example scenario:

1. Delete a page
2. Use Revdel for something like only some edit summaries
3. Restore the page

This results in the page being restored, but the revdel'ed summaries staying revdel'ed

Also, the page could be deleted, and certain revisions are further revdel'd with suppression options.

Basically, this sounds like a useful feature, not a bug.

In T242823#5804161, @Xaosflux wrote:

Couldn't this still be warranted? Example scenario:

1. Delete a page
2. Use Revdel for something like only some edit summaries
3. Restore the page

This results in the page being restored, but the revdel'ed summaries staying revdel'ed

Also, the page could be deleted, and certain revisions are further revdel'd with suppression options.

Basically, this sounds like a useful feature, not a bug.

It makes sense to be able to suppress deleted revisions, but not delete them, in my opinion.
As for the first example, if partial undeletion is desired, then it should be possible to partially undelete revisions, but not "delete" a deleted page's revision

But one of the best revdel-related improvements lately is persistence of revdel status during deletion/undeletion (and choice thereof). I certainly wouldn't want to do away with that, i.e. have all revdel status reset on deletion. Likewise, it's unlikely but if a page with extensive history is deleted, allowing revdel of those deleted revs means that if it is restored, they will still be revdel'd. Unlikely, but far from unheard of, with both revdel and suppression status.

Also, I know researchers can't see deleted text, but can they see edit summaries or usernames? There are also some tools for which being able to revdel deleted pages is helpful...

I think it's largely silly, but there are a few weird cases where it's useful. I can also imagine a world where sysops can revdel AbuseLog entries and a connection to deleted revs isn't removed where this is desirable.

@Amorymeltzer:
If revision has a revdel'd summary, researches can not normally view it - however, if the entire page is then also deleted, researches can view the revdeled edit summary. The same is for revdel'd usernames.

--This seems like a bug, but not sure if it is because there is a leak, or because the feature is only half working. -- Could be be design to, this information is available to researchers - but only if they specifically go looking for it.

The normal rights deletedtext and deletedhistory does not allow to view revdeled content.
In my opinion it could be a valid way to revdel archive, if private information should be hidden to a smaller group, when both rights are given to other groups than sysop.

I would support a decline here.

I don't see a bug here either. Before restoring a page, a need may arise to rev-delete a certain revision. This feature makes that perfectly possible and effective now.

If this is disabled, that means the page has to be first restored. Then the admin rev-deletes the revision in question while hoping that nobody (who is not eligible to view it) already open it.

Actual result:
Revision deletion goes through, but doesn't really mean anything

No. The rev-deletion will persist whenever the page is restored. That do means something, very important.