Plot magnetic heading and gps heading from ulg files

Hi,
I’m trying to plot gps heading and mag heading from the ulg file from a flight. I’m using PlotJuggler and I’m familiar with plotting but not with the PX4 firmware and the name of the instance to plot. Is there a manual that explains the “names” in the ulg file.
The problem is I can’t find anything related to a heading shown in degrees.

/Joel