All Overlord projects are completely open source, released under the Apache License, v2.0. So, not only is the code available, but it's completely free to use and modify! Nearly everything we do is online and public:
Contributions of any type or scope are immensely helpful! Regardless if you help other users in the forum or chat room, improve documentation, improve this website, report/investigate bugs, or hack on the code, any type of contribution will drive the project forward. If you're interested, feel free to reach out to any team member on IRC or in the forums! Thanks for considering!
A great place to start is to look through the READMEs for each sub-project: