On the phabricator pages folks discuss some obscure feature related to file uploads on phab. I vaguely recall that I added links to two images on phab as "other versions" on a commons file. So where was this, how can I find it again? Maybe Special:Contributions should offer a search limited to all pages edited by the given user.
Topic on Help talk:CirrusSearch
I don't know if worth it, but this could be feasible, "simply" dumping the history into ElasticSearch. Even just usernames would end up being huge, though.