One team documents the protocol as a spec. A second team takes the spec and writes implementations. The advantage of this for open source is that when the protocol changes, it's relatively simple for that first team to update the spec, and safe for the second team to update their code.
This is legal and safe. It is how the first clone PCs survived even IBM's lawyers.
This is legal and safe. It is how the first clone PCs survived even IBM's lawyers.