SolvedTSEM6523 | Legal background to trusts and estates: Scottish law: confirmation
From HM Revenue & Customs · Trusts, Settlements and Estates Manual
Confirmation is the legal authority under which an executor acts. It indicates that the Sheriff has confirmed the executor’s right to act in connection with the estate.
An executor gets the confirmation from the Sheriff’s Clerk’s Office. Normally this will be before HMRC tax office is involved.