Altitude problem

I am confused about the unit of filed_altitude in Flightaware data. For example, a flight from Hong Kong to Memphis, USA, with a distance of 9300 nautical miles and a value of 270 for filed_altitude, I am confused whether the filed_altitude here refers to the average altitude or the altitude during the cruise phase, and what is its unit?

FL270 being flight level 270 filed against plan for cruise.

Aka 27,000ft

That’ll be the requested level from the pilots to meet performance calcs. May be approved or overridden by control.