What you mean is "concede" - an opponent's right, anchored in the official golf rules.
A gimme ("given") has always been inofficial, outside the rules and only for use in private rounds, applied by fellows or the player himself on short putts. Here, it's used in a very dedicated way, only as a "self-gimme" in limited situations, for lower tier players OR in practice games.
Unfortunately, there's no mentioning in the FAQs yet.