Session
Login with Floatplane (OAuth, optional)
Floatplane's own apps and third-party clients log in through an OAuth device flow instead of a cookie.
That needs a client id issued by Floatplane for this plugin — there is no self-service registration.
If you have one, enter it and press "Login with Floatplane"; the OAuth session then replaces the cookie
(refresh tokens last about 90 days and renew themselves).