[summm]

Unfortunately you have generated a name collision: the server component of the Mumble VoIP is also called "Murmur", for a long time: https://en.m.wikipedia.org/wiki/Mumble_(software)

[numpad0]

Yeah, I think that fully explain apparent disinterest of users. No way nobody is looking for this app, but there is also no way this one shows up on searches over the other one.