Does a z-wave extender need an app I wonder, it has no funtionality other than relaying messages and I assume (!) adding it to a network is sufficient. @Caseda
Any powered Z-wave device will work as repeater just fine indeed, supported in an app or not (does have to be included into the network/Homey (Bridge/Pro)), so that includes this repeater.
Actually, the ring extender will send a message to the hub when the power is off (It has a battery). So, this is the main reason why I think to support it. It will work when added, but the “AC Power” on/off function wont work.