There is a broken link in the README linking to https://maven.mcmoddev.com/net/darkhax/. You may want to update this to link to the current repository at https://maven.blamejared.com/net/darkhax/bookshelf/.

(Might also want to document inclusion in Fabric mods while you're at it?)

Thanks for letting me know. I've updated the info now in 8496a8d