Gyro .getAngle Axis

what measurement (from which axis) does the .getAngle return? I cannot find it in the documentation…

From documentation:

Return the actual angle in degrees that the robot is currently facing. The angle is based on the current accumulator value corrected by the oversampling rate, the gyro type and the A/D calibration values. The angle is continuous, that is it will continue from 360 to 361 degrees. This allows algorithms that wouldn’t want to see a discontinuity in the gyro output as it sweeps past from 360 to 0 on the second time around.

So it gets the angle of the drive base’s direction, which I think is z.