Account for profit
What an agent must do if it profits (without permission) with its principal’s property; what a thief (or breacher of copyright) must do to its victim with the ill-gotten gains of its misfeasance. Importantly, not what a breacher of contract must do to an innocent counterparty: there the measure of compensation is the innocent party’s loss.
Account for profits is a common-law remedy for misuse of another’s property. It is not a remedy for breach of contract.