Reposting this warning from @IanColdwater on the bird site:
if there is any account you have anywhere that you log into via Twitter that you depend on for anything important, I highly HIGHLY recommend setting up an alternative way to log in before February 9. Don't put it off. You will lose access to that account if you don't.
The "no more free access" footgun that the Musk employees are firing will also take down many places that have "log in with Twitter" there.
I just figured it would take down all the interesting automated accounts and maybe third-party twitter clients, but it looks like they want to remove that stream of login data too.