This cleanup task was prompted by a discussion of the handling of verbal nouns, which we carried out at Module talk:bg-verb. This subsumed the discussion of how verbal nouns should be generated using accelerated editing, as well as flaws with the existing accelerated system that allowed people to erroneously create verbal nouns forms that didn't exist.
Specifically, those verbal noun plurals ending in -та (-ta) were often of dubious character, as the typical plural of verbal nouns is -ия (-ija). In the past, numerous verbal nouns solecisticlly ending in -та (-ta) were created either by bots, or by accelerated editing, which we judged were clearly not real forms and needed deleting. This prompted a Request for deletion, whose entries you can see at User:Kiril kovachev/RFD BG Verbal nouns — there are quite a lot.
Then, there was also a task concerning how we wanted to treat verbal nouns using {{infl of}}: some pages used {{infl of|(verb)||indef|s|vnoun}}, as opposed to {{verbal noun of}}; and others used {{infl of|(verb)||def|s|vnoun}}, as opposed to {{infl of|(verbal noun)||def|s}}. Both of these transformations, both to using {{verbal noun of}} and considering inflections of verbal nouns relative to the verbal nouns themselves, as opposed to the root verb, were handled by this cleanup task.
All in all, this appears to have run without issue, processing 2636 entries and deleting around 859 fake forms (some of which were edited shortly beforehand to at least use the desired format).