I do not fully understand LiDAR Return Values, as opposed to Class Codes.
Both Arc and LAStools have options for selecting returns based these "values". For example, here is the Arc 10.7.1 Make LAS Dataset Layer tool, which has a "Return Values" section (LAStools has similar Return Values):
Furthermore, ESRI documentation describes Class Codes, but I can't find anything in their documentation about Return Values.
Importantly, these "values" are not mentioned in the ASPRS LAS Specifications, which I assume (perhaps incorrectly) is the official repository of all things LAS.
I would like to learn more about these Return Values: Are there any published standards? How are they derived? Are their values consistent between different software packages?