TL;DR: we can mass hide vandal revisions from pages histories, e.g. obscene images and edit comments.

Of course, this needs admin rights.
It is easy to mass hide revisions from the history of one page without bot, just click checkboxes. But it is tiring, if several pages are involved.

I wrote a script that is not ready to publish, and I won't show it for the vandal, and needs manual editing. But I can send it in a private mail to those who are interested.

The API documentation is here:
https://www.mediawiki.org/wiki/API:Revisiondelete
But it is not complete. I learned on my own that multiple revids may concern the same page. We don't have to write the title into the request, but must group the revisions by page.
The required format is e.g. 27009438|27009402|27009353|27009335|27009151 with pipe, all ids belong to the same page, otherwise they won't all be processed, just the first page. This is an undocumentetd feature. :-)

Sample code fragment (run with -user:myadminaccount):

hide = 'content|comment|user'  # Just to show the syntax, keep what you need
reason = 'Vandalism'

def gen() -> Iterator[str]:
    """Yield ids to hide in the above form, page by page. Here comes your work."""
    yield' 27009438|27009402|27009353|27009335|27009151'  # Example

token = site.get_tokens(['csrf']).get('csrf')  # get a single token
for ids in gen():
    params = {'action': 'revisiondelete',
              'type': 'revision',
              'ids': ids,
              'hide': hide,
              'token': token,
              'reason': reason,
             }
    request = site.simple_request(**params)
    request.submit()


To get the ids use for contrib in user.contributions():
contrib[0] will be the page object, while  contrib[1] the revision id for each contribution.
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Bináris