After the first one, I wrote another search provider for gnome-shell >= 3.6 in python, this time for flipping through your github repositories.
A standing problem is how to prompt the user for their authentication tokens. Right now, I require that the user maintain a ~/.search-github file by hand including their github username and password. Ugly, but it works.
Best, I think, would be to integrate with GNOME Online Accounts. However, it appears that I cannot write a plugin for that.
What other approaches are available? I could use a modal prompt kind of like when NetworkManager prompts you for a wifi or VPN password and could then save credentials to the keyring. I haven't yet figured out how to create that prompt yet though, so if anyone knows.. kindly point me in the right direction.