CoinHive. Lot's of cryptocurrency mining in the library scripts on Greasy Fork
https://greasyfork.org/en/forum/discussion/30009/is-monetizing-a-script-with-coinhive-not-allowed/p1
If they are hiding the fact that it uses coinhive, you can report it. Otherwise it is fine.
Considering it looked like the case in 2 of 4 library scripts I looked at, it seemed like something that should be handled semi-automaticly... :-/
CoinHive. Lot's of cryptocurrency mining in the library scripts on Greasy Fork
Looking at code in a few random libraries in https://greasyfork.org/en/scripts/libraries , I found several with CoinHive code. I assume that is not allowed here? There's no information about CoinHive in the descriptions of the scripts...