Can we find a better name than _RELATED? IMO it doesn't suggest that it wont be loaded.
Correct, it suggest that it _may_ be loaded (by the proxy) and is related to a "matched" one, but is not matched itself. It makes sense from the proxy plugin's point of view. If you look at it from Geany's point of view, then NOLOAD makes some kind of sense, but this is the proxy plugin API so it should be from that perspective, IMO.