How does “Bank details” work on the Contact Sync page?

A bank pair reaches Xero through one gate: an Admin's approval on the Bank details tab. The queue is worked in money-at-risk order — mismatches first, then the unverified, the biggest outstanding bills first inside each band. Account numbers arrive masked and are revealed on an audited click; every number is a button that jumps to the bill that actually carries it, highlighted on the page, because reconciling a sort code against a bill that never printed one proves nothing. A pair matched digit for digit by a fraud-clear bill can be approved and pushed in bulk; a pair that cannot exist is refused on the server too. Where: Contact Sync (/accounts/contacts-harmonisation).