Hidden microphone noise suppression added (voice_webrtc_apm), off by default
The October 22 update's notes only cover map scripting, but the game files added WebRTC microphone processing (noise suppression, echo cancellation, gain control, high-pass filter). It is off by default, not in the settings menu, and is turned on in the console with voice_in_process 1 and voice_webrtc_apm 1.