Multi-channel audio is common in a video with sound and each channel is displayed with its own layer in Spotlight. Video with only one channel is called mono. Video with two channels is most often stereo audio, one channel for the left microphone and one channel for the right microphone.
The example track above is multi-channel audio but it is NOT stereo audio. The audio in this dashcam video comes from two different sources. The first source, Audio 1, is the audio captured from the dashcam. Audio 0 is from the radio feed.
You can redact the audio from both tracks simultaneously or individually based on your configuration and requirements.