(ANSWERED) Login account info passed on in Steam backups - Technischer Support

Temporina

... but I still do not understand where it picked up the password to login into Steam.

1. Was the password only for the first ever logging into Ryzom?

Game account will be linked to Steam account after the first time you press 'play' on Steam interface and login into game using game user/password.

Second time your press 'play' on Steam interface, game signs you in using Steam account ID.