The owlauth-spec repository holds the documentation, including specification, for a new authentication protocol called Owlauth.
Owlauth is still in development. An initial server implementation and client library is working, but not yet published.
The specification is available as an initial write-up here: https://github.com/owlfish/owlauth-spec/blob/master/Specification.md
A test application is now running at https://owlfish.com/larder . The application uses Owlauth for login and implements a fallback to email based authentication for domains that do not have an Owlauth server running. Feel free to give it a try!