Here are some more examples:

https://musescore.com/nicolas/scores/437

It's listed as: Creative Commons copyright waiver

https://creativecommons.org/publicdomain/zero/1.0/

https://musescore.com/user/48985/scores/70596

It's listed as: None (All rights reserved)

This is an extremely cool part of the game that SE has implemented but to implement it, state accounts will be perma-banned if copy right if violated, and not give players some guidance is disappointing. At least a list of acceptable copy right options and the path to submit proof if a GM or another player reports them vs an unquestionable perma-ban.