Where are Apple mail passwords saved in Sequoia?

I have a working mail account of which I need the password to use for webmail. The password used to be accessible in the keychain but that appears to have disappeared. The password cannot be found in the passwords app and if I go to

System settings > Internet accounts > Details...

or

Mail > Settings > Accounts > Server Settings

I see the censored password (which seems editable?) but cannot get it to reveal. (See screenshots).

Where can I find the password now?