Any asset can be split into as many segments as you want. This way you can split asset to put commercial between segments and leave original clip unchanged. This number indicates the segment number.
Example:
Asset starting at 11.51.47 and has 2 commercial breaks. First at 11.52.41 and second at 11.56.02.
NOTE: You can segment asset which only has audio keyframe set on every keyframe (raw audio).