How to get real-time data and know what the data variable name is...?

Currently SITL with MAVProxy and X-plane. I want to be able to know what the values of calculated data within ArduPlane so I can figure out what is going on.

I have seen documentation on the graphing module but I don’t know how and where to look up the data variable name.

Hints and tips please?

Take a look at the "mavlink messages documentation"
And make sure that you activate the correct SR1_* data streams.
For copter there is a tool that helps you determine what streams you want to activate and help you determine their maximum data rate.
pymavlink/tools/telemetry_datarates.py

ta for the tip! I’ll check that out on the morrow. time for bed!