concrete5/concrete5-5.7.0 — pull request #1350 by KorvinSzanto (2014-10-16 06:30:46+00:00)
Title: Add detach button to oauth authentication types

This presents a pretty serious issue: if a user creates an account with facebook login, then detaches, it will cause the user to lose the ability to log in.
After completing it, I'd much rather leave this for the next point release accompanied by something like `$user->getRegisteredAuthTypeHandle()` to prevent detaching the auth type you registered with.