Since OpenID was removed in July 2018, a Launchpad Login button appeared*. Previously, this button had appeared and disappeared over the year, which was why I got into the habit of logging in with my launchpad.net/~username URL, but now I don't need to, and it appears to be solid.
I like it.
I presume it's not OpenID, so what method are we using for SSO with Launchpad now?
Since in my research of this question I also stumbled upon discussions of old "Ubuntu SSO" vs "Launchpad OpenID", how locked in are we to this new SSO mechanism, whatever it is?
*(I don't log out very often so, outside of the OpenID removal I'm a bit unaware, forgive me if these changes have been discussed).