Please see this issue on why Fewbricks is not in the WordPress Plugin Directory.
Fewbricks2 is a complete rewrite of Fewbricks and introduces an insane amount of breaking changes so don't even try installing it in a setup that is already implemented using Fewbricks1
Fewbricks is released under GPLv3 and is in no way associated with Advanced Custom Fields.
The documentation can be found at https://fewbricks2.folbert.com/ or as MD-files in the folder "docs" in this repo.