Coffee Bar is one of the MacBook Air cafes, places where almost everyone is on a computer, typically a MacBook Air. It's unclear what generation of cafe we're on in San Francisco, but this one is in the "sleep, airy, mostly white/gray pallet, wooden tables, green plants" style - the Macbook Air of cafe.
Coffee Bar has complicated rules about computer usage at tables at different times. Basically, from 11:30AM-2PM, a large percentage of the tables are reserved for 30 minute lunches.
In terms of food, they lean toward the contemporary California style (salads, organic sandwiches, etc.). They have bottled expensive juices and very expensive (and great) bottled iced coffees.
Expect there to be at least one well-marked Stripe employee at the cafe at any given time (sometimes T-shirts, sometimes stickers on their laptop) because the Stripe office is just a few blocks away.
1890 Bryant St
Likelihood of overhearing annoying startup talk: Pretty low, this isn't a super talky kind of place
Likelihood of sitting next to someone toiling away in the digital mines: high (in fact, you might be that person)