What's the difference between unique territory number and territory number?

The unique territory number and territory number are both user-friendly public identifiers for a territory. If updates are made to active territories only, using Import Management or the Less Details territory UI, then the unique territory number and territory number are the same.

If updates are made to territories in a proposal using Import Management or the territory More Details UI. then the unique territory number and territory number are different when there's a draft version of the territory (the territory is in a proposal). When the proposal is activated, the unique territory number is replaced by the territory number. (This assumes the Retain Territory Version option is enabled.)