Where, then, is the right place to request this? It seems like a software matter.

You want an AbuseFilter created. Those are carried out by local wiki users. Wikis have different policies on this.

Phabricator, like Bugzilla, does not track tasks that need to be taken by individual wikis rather than in the software itself.

Assuming, then, that an edit filter is created locally, where do I address the matter of showing those pages on the special pages? Is that a software matter?

You want to show the edits your filter catches... Where exactly?

On Special:NewPages and Special:NewPagesFeed, along with the strictly newly created pages that are shown there now. In addition, on Special:NewPagesFeed, there should be a new search filter, like the ones already present, to include or exclude these pages. Would that fall under the project MediaWiki-exensions-PageCuration?

I guess you'd have to develop a filter consequence/action that can somehow mark the edit as New page creation, if possible? We do currently have a hacky way of forcing another one of these types of flags (markbotedits for rollback). I don't know if this would be allowed but you could try creating a task against AbuseFilter and see. All NewPagesFeed stuff would indeed be in PageTriage.

Ok. I'll get the filter created first, then create another task if necessary. Thanks for your help!