Encapsulate the usage of other auth.* drivers, to allow multiple sources of users. It can work either in Master/Slave mode (master is read-only, slave is read-write for shared users), or in "User-choice" mode where users can choose at login time wich method to use for authentication.

Master/Slave Mode: this is useful to connect Pydio to an external user directory that is not writeable. Typical example would be an LDAP / AD directory. To still be able to share resources with external users, setting a "local" sql-based driver as Slave will allow pydio to create shared users in the local DB.

Users'choice: configure two authentication drivers and let your user choose which method to use at login time. This can for example let user declare themselves as internal or external.