Hmm, apparently for steamgifts it means that it would be only activated in Germany, because once I log into steamgifts via my Steam acc I can view the GA that are Region Restricted Germany and when I log out I can see all Region Restricted ones, meaning Steamgifts takes my place of Residence as reference. This is truly confusing.

I actually just won SR2 from another GA here on Steamgifts that also made it Region Restricted Germany and it actually was the German Retail version and I could activate it.

I might need to contact Steamgifts (or Steam itself) about it because it seems not only I seem to be confused by the whole region restriction thing and Steam's FAQs where not helpful in their wording either.