This is a central repo hosting protocol buffers. All packages contain the generated code for any desired languages.
For Go, follow these steps:
$ go env -w GOPRIVATE="github.com/SB-IM"
$ git config --global url."git@github.com:".insteadOf "https://github.com/"
Then, you can get it with (use signal package for example):
$ go get github.com/SB-IM/pb/signal