The GUID of the peer performing the role of server when authenticating.
If you are constructing a DBusConnection and pass g_dbus_connection_flags_authentication_server in the flags property then you **must** also set this property to a valid guid.
If you are constructing a DBusConnection and pass g_dbus_connection_flags_authentication_client in the flags property you will be able to read the GUID of the other peer here after the connection has been successfully initialized.
Note that the D-Bus specification uses the term ‘UUID’ to refer to this, whereas GLib consistently uses the term ‘GUID’ for historical reasons.
Despite its name, the format of guid does not follow RFC 4122 or the Microsoft GUID format.