Last week I was working on the Contacts addon, getting it into Thunderbird. A couple of its importers use OAuth, which in TB was a bit clumsy. It had to open a browser tab, let you authenticate, then you had to copy a key and paste it back into the Contacts tab. Not the best UX (an OAuth issue, not a Contacts issue). I decided to put together an addon that could be used by other addons to perform OAuth, at the same time getting rid of that copy/paste process. The UX is certainly not finished, and every OAuth provider has a different layout for OAuth, but at least it provides a consistent experience that we can build on. If you’re interested in playing with it, you can find oauthorizer in my bitbucket repositories. It is not integrated with anything else yet so as no end-user usefulness at this time. If I can find time soon, I’ll get a patch together for Contacts.