This is a (very small & partial) disassembly annotation of the ZX81 ROM. It is by no means complete - it only has the annotations I wrote up when trying to figure out how the program listing routines for another project I did.
I'm sharing it here because although significant portions of the ROM have been annotated in Logan & O'Hara's book, a lot of the details of the functions aren't, which led me to doing this.
For the most part, this is my best effort at working out what the code is doing, and may have gotten some of the details wrong. The notes are written in an Excel sheet.