Originally Posted by G Series Manual
The Meridian Configuration Application is an alternative to using the Configuration Wizard, or you can view or modify a configuration previously created using the Configuration Wizard. It also provides control over several features not available from the front panel, including programming of the soft keys.
Suggests that renaming sources might only be available via Config.

Main system - Sources (Kodi-HTPC, Vero 4k, FireTV, Sat) into Trinnov Altitude 32 (8-16) (+Roon), Trinnov Amplitude 8 amp & Vivid Audio (Giya G3, V1.5) and REL Stentor III speakers. Others: F80 + Raspberry Pi and other Pi systems.