How can they request that? Also, it's Youtube's stated policy that all copyright strikes must include the details. Also also, the creator did request the details of the strikes and Youtube didn't provide any.
> If you cover a song, and get a copyright strike, is it not fairly obvious what the strike is about?
No, it's not. There are numerous instances where companies would issue blanket copyright strikes even for content those companies don't have a copyright to [1]. There are instances where there are copyright strikes for silence and for bird noises [2]. Copyright strikes are anything but obvious, even for cover songs.
[1] https://www.ccn.com/youtube-has-massive-false-copyright-clai...
[2] https://www.bbc.com/news/technology-42580523 and https://thenextweb.com/google/2012/02/27/a-copyright-claim-o...
But given the channel in question, the notice & details are really not a mystery? If you cover a song, and get a copyright strike, is it not fairly obvious what the strike is about?