In the last episode of
<
mailman.4411.1432305032....@lists.mozilla.org>,
Google doesn't want applications storing passwords at all, and for good
reason. Instead, they want to know passwords come from users, OAuth
tokens come from applications (and are not shared between applications).
This switch tells Google to accept passwords via protocols that support
password based authentication.
New versions of Thunderbird should support Google's OAUTH, but out of
date versions won't.