Architecture & practice·Teams, ownership and Conway's law
one person was on holiday and the release could not go out until they got back.
Bus factor
Also calledtruck factor, lottery factor, key person risk
The number of people who would have to be unavailable before work stops. It is usually one, and it is usually one for reasons nobody chose: the person who set up the pipeline, the only one with the production credential, the only one who understands the pricing rules. It is worth raising in planning rather than after the fact, because the fix — pairing, documentation, rotating who does the scary task — takes weeks and only works before the absence.