The master configuration file that holds all the commands that OLP texts use to typeset things — the file you mainly want to change to adapt OLP to your own needs — is now documented. The LaTeX comments that document it are written in Markdown, and the comments are automagically converted into a nice PDF that serves as a reference guide for the commands. Find it under “builds” as open-logic-config.pdf.
Additional documentation, of course, is all on the GitHub wiki.