While making some changes with XF 1.3.0 I had a media site definition that existed on two sites, Site A & Site B. On Site A the definition was associated with an add-on, on Site B it was not.
When I exported the add-on from Site A and then imported to Site B the existing media site definition still showed as not being associated with the newly imported add-on.
Bug or by design? I can understand why it'd be ' by design' since it helps to avoid overwriting an existing settings that are not associated by the add-on but at the same time there may be instances where existing media site definitions that are not already associated with an add-on might want to be overwritten by an add-on (eg: somebody has an add-on that completely overhauls "youtube" embeds and wants to export it for others to use).
I'm good either way, just figured I'd put it out there in case.