Is this for say AppImages? Is there a simple way to extract the AppStream data from an AppImage?

Does it affect any other uploads?

Primarily for AppImages i guess, but also for source uploads, as well as flatpakref and snap uploads. Basically, this would tie into the whole "we need to be able to provide specific assistance for specific categories" thing, like linting of for example kpackage uploads (like plasma applets, which require a specific internal layout). Essentially helping people to correctly fill out their store listings. The first part is more work, but the second can be just sort of... done, i guess, by adding it manually (which would be something like appstream##id=org.freedesktop.ocstester as suggested in the tags proposal in T6133)