Clarification needed on third party user login

I am trying to create functionality to log in users from a third party database using generateSessionToken()

According to the docs: generateSessionToken - Velo API Reference -
If a user does not exist in the wix members database a new user will be created with a random password.

Are these users permanent? Or are they removed from the database after logging out? If they are permanent then how is their password verified next time they log in? Or is the password not even used?

I haven’t used this before so I don’t have an answer for your question currently, but I did want to say that you should use the function under the wix-members API . Wix Users works but is deprecated.