Tried to join two data together in javascript but cant figure out what does "aq" mean here.

data = aq
  .from(demand)
  .join(aq.from(temperature_with_features))
  .rename({ air_temp: "temp", value: "demand" })
  .select(aq.not("id", "name"))
  .objects()

The complete code is here:https://observablehq.com/@observablehq/correlation-over-time