Flightware altitude vs. altimeter

[jonhawkes2030]

Flight aware reports transponder or pressure altitude (ie 29.92Inhg or 1013.4mb).
FAA ground stations correct for this.

This was talked about a few days ago

General confusion about aircraft/ADS-B altitude

Disclaimer: I’ve read the FAQ on this, but I’m going to ask again with a focus on the FlightAware Pro Stick Plus, specifically: Hello. I’m using the FlightAware Pro Stick Plus v1.0, Mode S Receiver using dump1090 --net mode, and I’m trying to understand exactly what is meant by the returned altitude field (in general, or the most frequently returned altitude. I understand that there will be some oddball aircraft out there using different measurement methods, but I’m just concerned with the most…