Aircraft certification requires an emergency egress within a specified amount of time hence a certain amount of emergency exits.
If there is such a requirement for a full jet bridge I haven’t heard of one.
If the gate agents don’t work for the airline as in they work for a subcontractor ( the lowest bidder) they will be penalized for late closing of the boarding door.
Delay codes are frequently:
- flight crew ( late arrival)
- cabin crew ( late arrival)
- cleaners (delays)
- maintenance (issues)
- gate agents
Or something similar as different airlines may use different codes/descriptions.
Be kind to (subcontracted) gate agents as their jobs may literally be on the line.
They’re generally close to minimum wage and they don’t get travel benefits either.