I used to be able to click a tag, click "open tasks" on the sidebar and see a list of open reports for that project. (T89865 made that slower but still feasible, at least for people with good enough CPUs and networking.) Nowadays, I have no idea how to reach the same result in less than 10 clicks or so (e.g. manually building a query from Maniphest Advanced search).
Upstream task (with potential Phabricator extension code): T10308 Please undo some changes