LD HL, 402Bh
LD B, 0Ah
LD A (HL)
LD (IX + 0), A
I think it became part of a bigger “Hexmon” program to display chunks of internal memory on screen.
- A macro-assembler in 96 lines (1300 bytes of object code) (atariwiki.strotmann.de)
- Mining for optimal assembly sequences (thecodecavern.co.uk)