Her 2021 post.
… talking about the user password (not the LUKS password).
The user password is the password of the purism account. This would be the login password for the purism account if the Librem 5 used the login screen (like a regular Linux computer, but it doesn’t).
The user password is used to unlock the lock screen initially after boot (after the LUKS password has long ago been successfully entered) and is used to unlock the phone any time that it locks itself due to inactivity.
The user password is like the unlock PIN used on a mainstream spyphone.