This Mumble Moderator module creates a Low bw channel whenever a member of group “bots” enters a room. This channel is linked to the channel the bot sits in but the bot does not have permission to speak. This saves bandwidth for users with low bandwidth.
Technical background: If you local mute someone you still get his audio stream but it is discarded locally; it still needs bandwidth.
More information in the blog, see here.
The Code and the configuration file can be found on Github: