@me@SDF Well, it’s a PDP-6/-10 HALT instruction (a variation on the JRST branch instruction), but I don’t know the significance of the 18 bit address field (277616).
The original XKL logo had an address field which was the SIXBIT for WA<space>. After a reorg and name change, I redid the logo to have an address that decoded to LLC .
SDF