Propellor is free software, released under a BSD license. Anyone is free to modify and distribute it; indeed doing so is a fundamental part of how propellor is configured and used. You don't have to contribute your patches, but you're encouraged to do so; let's all make propellor awesome together! Also, contributing patches is a good way to make sure that your code keeps working in new versions of propellor. See [[interface_stability]]. Patches can be sent to or pull requests can be posted to [[todo]]. To certify that a change is released under propellor's BSD license, you can use `git commit --signoff`. Propellor has its own [[coding_style]], which you are encouraged to follow -- at least when you want to get a patch merged into propellor. When writing code for your own internal use, feel free to ignore all the rules, except the ones about avoiding partial functions.