I use a custom keyboard with a REPL key (shifted: Settings) that I have bound to XF86Send (shifted: XF86Tools). On Fedora 21, that key (XF86Send) somehow works to toggle the mute on this laptop's internal microphone. I get the same kind of symbol-on-black-glass as the normal volume keys, and the Sound panel in Settings shows the toggle switch moving (Settings  Sound  Input  Input Volume  On/Off). However, unlike the volume up/down/mute keys, there doesn't seem to be a place to rebind this key in Settings  Keyboard  Shortcuts  Sound and Media (nor anywhere else that I've checked).This prevents the key from appearing to applications (eg I have it bound to bring up a REPL or similar sessions in Emacs for various languages). xev shows some line noise, but no real keystroke, and <Help> k <XF86Send> in Emacs never gets the REPL/Send keystroke (it still awaits with Describe key (or click menu):)Is this a part of the Gnome Shell, or some other coperating program?Or, more significantly:Can I remove this binding, maybe via dconf editing or something?
Gnome-shell keybinding for Internal Microphone on XF86Send
fedora;pulseaudio;gnome shell;xkb