Trimming used to mean the start and the end. Now you can split your video on a timeline and remove any section in between, so a stumble halfway through no longer means recording the whole thing again.
Preview the cut before you save. Restore anything you change your mind about. The result plays back as one video, not a stitched playlist, and your original is always recoverable.
The editor also uses more of your screen now, with millisecond-precise readouts for landing a cut exactly where you want it.