I want a Site Guest User to be able to hit a page that uses Apex to do an API call. However, if I create a Named Credential of type 'Named Principal', then that credential is simply missing from the list of available credentials when you try to grant guest profile access.
If I make it a 'Per User' named credential, then it appears in the list of credentials I can give access to that user, however there is nowhere I can go to set the password for that user. Normal users can login and set it themselves, but a guest user by definition cannot.
How on earth do I do this?