Since gaming now lives at http://YouTube.com/gaming , the old Gaming app is going away on May 30th! If you were subscribed to channels in the Gaming app, they’ll automatically move to your YouTube subs feed on May 14th. More need-to-know info→ https://yt.be/help/yRe4
I was watching a youtuber called Mumbojumbo, then 1800 of his videos got claimed, because he used music he was allowed to use, and he can't claim all 1800 one by one, so help him.