The master user account is a special non-OS user account that provides direct access to the administrative console without authenticating to the Local OS or Active Directory. The master user is defined during the installation process.
The master user should be used to delegate administrative rights to other users added into the system and should NOT be used as the main conduit for administering the system and application. The master account credentials can be changed by the master account or by full-access administrators. It cannot be changed by any other administrative type.
The master user can view all Content tabs, on condition that the datasource user (described below) has been defined in the "Users" list.