It's the lowest aid-climbing grade. Expect a fixed bolt or peg that you'll need to clip and pull on to get past a stopper move, the rest of the pitch being climbable free at 5.7.
It might, also, be a fixed-pendulum. (For example, pitch 9 of Royal Arches in Yosemite is 5.7 A0 because it has a fixed pendulum. Probably 5.10b without.)
The most polite comment you can make when the leader takes a rest on gear for the umpteenth time on a pitch is: "I didn't realise this climb was VS A0."
