If the concern is pruning old/stale/invalid issues/PRs, I think the proposal to add a specific "awaiting-close" (or similar) label should work. These issues can periodically be handled by a core-dev who can click on the label, then evaluate and bulk-close them in one shot if necessary. Also, it seems to me that including "devguide" and "core-workflow" repos is unnecessary since they are low-traffic administrative repos related to our internal workflow, they are attended by a small portion of the core-dev team only and labels don't play a central role as in the cpython repo. Please let's keep in mind that this role implies higher responsibilities than a usual contributor, and since the bar for being promoted is considerably lower than a core-dev's, triager permissions should reflect that and remain minimal. For instance, I don't think a triager should be able to edit other users' comments or lock conversations, but I'm afraid GitHub doesn't provide that level of granularity (correct?).

--
Giampaolo - http://grodola.blogspot.com