Units for "Onboard Message Log Messages" variables

Hi. I’ve been given an ArduPilot MatLab format data file to examine. Field names in the file are from the “Onboard Message Log Messages” found here: Onboard Message Log Messages — Copter documentation
There are time vectors (TimeUS - Time since system startup), and data values, but there are no units for the data values (e.g., meters, feet, etc.).

There are XML files related to “Getting and Setting Parameters” for MavLink here:
They have units, but not the same field names.

Would someone know where I could get the units for the variables here:

I’m 100% new to ArduPilot, so if anyone can suggest a good starting tutorial, I’d be grateful.

Thank you!

In a log file such data is in GMT messages.