Hello, we are trying to download the recommended build for versions 1.8-1.20.2, which is 673, however when we click on the link it doesn't exist.
URL: https://ci.dmulloy2.net/job/ProtocolLib/673/

maybe you can try this https://ci.dmulloy2.net/job/ProtocolLib/679/

If anyone desperately needs ProtocolLib-673.zip, I have attached it to this message. Alternatively, one can probably built it from source.