This is a restricted gift which can only be redeemed in certain countries. .... What Countries :c ?

isn't one of those games that is banned in some countries like Wolfenstein? idk

You know... THAT country...

Most of the times the gift is still ROW only that countries like Germany or Australia can't be redeemed there but for some reason it doesn't specify

Well maybe the country of certain. You should say what game it is. So we can find information about it.
To find a much more definite answer What game key that you redeemed and from what website?
But there is a discussion about it and the dev didn't set it up
https://steamcommunity.com/app/328600/discussions/0/624075036476026535/

The discussion is form 2014 and I am surprised as a Student Game dev that they did do anything in their hands to work it out.

Here is the info from the dev
"Hello, there are no settings within our control that allow us to specify region restrictions, I can assure you if there were, we'd open it up to all regions because that's how we would prefer the games that we play ourselves to work.

You may be able to contact Steam to ask why you can't trade your extra copy to different regions."

Yes it's just banned in some country . but basically a row gift

http://www.steamgifts.com/discussion/D6Suw/be-careful-with-x-pack-keys-from-bundles-that-give-gift-copies-when-you-activate-the-key

AFAIK standard "gift bought in store" restrictions apply.

So, South America can only gift to South America, Russians to Russians while countries without standard restrictions can gift it to everyone, just get this text due to some bug.

If your Steamcountry doesn't lie, for 99% it's world-wide gift.

Here

try redeem the gift, you will know what countries... relax will not outomatic adding to yr library