Patches may be submitted via a pull request on Bitbucket. Please note that unless explicitly stated in your code, all submissions will be assumed to be licensed under a 3-clause BSD license.
Despite this project being distributed as GPLv2+, several pieces of code are shared among other game engines which may not be under GPL compatible licenses. Additionally this project is dual licensed under the GPLv2+ and the original source code EULA (licensing option determined at compile time). Given these facts, outside of specific exceptions submissions must be made under the more liberal BSD license.
Exceptions may be allowed on a case by case basis, and need to be clearly documented.
For larger changes be sure to read PHILOSOPHY.md to ensure that your patch is inline with the project's stated goals.