This is a modal type 2. It is used for numeric input with axis motion. X, Y and Z entries use this type of modal. It is handled the same way as a numeric modal except it keeps track of the absolute position of the axis regardless of incremental or absolute mode. Use this modal for all axis type entries in the $pp file.
These lines determine that the X, Y, and Z axis calls are a modal type 2 because they are each axes called in the postprocessor. They would output a letter (X, Y, or Z) and either a 5.4 format in inch mode, or 6.2 format in metric mode each time one of them are called into play.