Summa

In which context would you expect your suggested feature to be useful?
It would be useful in the main menu and the tray menu next to the "Quit Mumble" buttons.

Describe the feature you have in mind
A clear and concise description of what you want to happen.
Restart the App.

Describe alternatives you've considered
Can't think of one.

The docs for BPF state that

The reciprocal of Q. Q is conventionally defined as cutoffFreq / bandwidth, meaning rq = (bandwidth / cutoffFreq).

Which is wrong for a band pass filter. cutoffFreq should be replaced with centerFreq, or maybe just freq, as that is the name of the parameter.

This is the help file:
'/Applications/SuperCollider.app/Contents/Resources/HelpSource/Classes/BPF.

For classes declared with struct, forward declarations should also use struct. Currently, only struct Message violates this in a few header files (2 or so?).