ed25519 has been removed by maintainer, breaking obfs4 builds and go gets
As of 2020-02-26 the maintainer of https://github.com/agl/ed25519/ has removed all their code, their releases, and everything to do with their ed25519 project.
This means building projects that import that module, without having the module in an old go
vendor directory fail.
go get -v git.torproject.org/pluggable-transports/obfs4.git/obfs4proxy package github.com/agl/ed25519/extra25519: cannot find package "github.com/agl/ed25519/extra25519"
As such this project cannot be built or included by anything that fetches it with
I'm not sure if this library is imported anywhere else, but it certainly is used in obfs4