Is there a reference for the assembler-like output produced by `awk -W dump`?

The command awk -W dump ... produces a dump of "assembler-like" code (as shown [here \[link\]][1] , or by reading the man). Some of the instructions are easy to guess at their meaning such as jz, which is produced by an if statement and is clearly a _jump zero_ instruction. But others are less so. Surprisingly, I can find no reference to the instruction set awk defines which seriously limits the utility of such output. Is there any such reference online?