LOITER_TO_ALT arguments

I was researching a LOITER_TO_ALT bug and found out that there are multiple conflicting descriptions of the parameters for the command:

  1. MavLink documentation points to heading required (p1) and xtrack (p4) parameters along with p2
  2. ArduPlane documentation points to only p1 and p2.
  3. The code itself stores p4 but doesn’t seem to capture p1 at all, and based on the actual behaviour code it seems that the “heading required” part is always active regardless, unlike what the documentation suggests.

Am I missing something or should Plane documentation be updated to reflect p4 being used and p1 being de-facto ignored?