There's a lot of snippets posted over the years on various forums. Nothing much, a few pages to get a hint of the syntax and the basics. Once you've picked apart the loader/runtime[1] the dynamic nature of the Lisp runtime system allows the system itself to hint a lot at how things originally went together. (e.g. type information is always present, state machines are explicit and easy to spot)

[1] http://www.codersnotes.com/notes/disassembling-jak/ (my old article this is based off)