Compare scans
Diff one scan against another, id by id, to see exactly what changed. Compare an org to its own past, or one environment to another. Source only, no org connection.
Change by type, up top
The per-type breakdown sits with the headline numbers: how many of each metadata type were added, removed, or changed.
What moved
The added, removed, and changed components in full, plus the risks that appeared or were resolved between the two scans.
Drift over time
Compare against saved snapshots of the same org to watch drift accumulate, or compare a sandbox to production to see the gap before a release.