...
If IX(in) = $FFFF then the following information is obtained:
FA_PTR:
DE = number of free handles
BC = OZ version number (OZ version is embedded in C register as two hex nibbles , ie- i.e. 44H for OZ V4.4 - however it's 03H for OZ 2.2 - 3.0, and 04H for OZ 4.0)
FA_EXT:
DEBC = estimate of free memory
FA_EOF:
Fz = 1, if Z88 is expanded, else Fz = 0
...