Sorry, could you provide a quick/rough English translation of one of those lines? I'm unfamiliar with APL or how Chinese characters are written with Latin symbols, so it would be useful for 'seeing' the syntax.
https://github.com/arcfide/Co-dfns#publications
You can read the "Key" paper that walks you through one of the core data structures in the compiler and how it works. If you see the "rn" binding in the compiler code in "e.cd" you'll see that code put into the first compiler pass of the project.
If you want to see more than that, I can email you a copy of an updated version of that paper which is currently under review (not likely to see publishing this round). It includes descriptions of the implementations of the "lf" and "fe" compiler passes.