Budget brake
A temporary budget cut on a campaign running far above target. A stopgap, not a fix.
When a campaign is spending well beyond its target with real money at stake, the fastest way to stop the bleeding is the budget, because it takes effect immediately while bid changes need time to re-price traffic.
AutoPPC is explicit that this is a stopgap: the reason always states that bids are the underlying fix. Brakes propose; they never auto-reverse. Restoring the budget is a separate decision you make when the bids are right.