Developer Guide
Alec my local version kept starting with this page. So I have tried to fix it. However there is no link for the "OpenCPN Developer Manual" at the top it is "file not found" Note that I renamed the "intro" files consistently.
I am not even sure these links are complete or needed, but this was part of the beginning of the manual
How to contribute to OpenCPN Code
The best way to contribute to OpenCPN code is to fork the main repository from https://github.com/OpenCPN/OpenCPN, push your changes to your fork and create a pull request. There is a short guide to the whole process at https://guides.github.com/activities/forking/