Make it easier to track category trees (Community Wishlist/W223/en)
For some editors, myself included, it's important to keep track of category trees of specific topics, e.g. "queer topics", "Agder", or "video games". On some projects, there are (active and inactive) bots that keep track of category trees and update some project page with a list, but it would be really handy to be able to see all the newest edits and pages in chosen categories (or a category tree – all subcategories of a provided category). This, or some similar system, would make it easier for editors with special interests to keep track of their most favourite topics!
I was primarily thinking about Wikipedia, but I can imagine that it would be useful on other similar wikis and Commons. I can also envision that it's useful for WikiProjects.
Unassigned
Contributors to projects with searchable categories