License is unclear
The README says
I'm also fine if you use this mod in your modpacks, just make sure to mention it.
However I don't allow clients or other mods to merge this mod without permission, if you would like to use this mod in your client or another mod please contact me.
This seems to contradict the GPL v3 license that's on this repo.
I assume this is actually just a case of dual licensing - that is, this permission blurb at the end of the description is an additional license you can distribute the mod under instead of the GPL v3, and a GPL v3 mod or client could very well merge this one, but if that's the case it would be nice to clarify that, potentially by making two LICENSE files (i.e. LICENSE.GPL and LICENSE.Modpacks).
Yes, I admit this is a bit nitpicky.