Hello and thanks for considering contributing to openPCells. This project is intended to be used and enhanced by many people, gathering different kinds of knowledge.
All kinds of contributions are welcome, including (but not limited to) feature requests, bug fixes, cell defintions, documentation enhancements and technology definitions. Furthermore, the provided cells are currently not being tested in many technologies, as this needs access to those. If you are working with integrated circuits and have technology access, testing the generated layouts of various cells with different parameter values is very valuable for improving the code of the cells.
I try to add stuff that needs fixing or implementing to the todo file. There is of course also the issue list on github, but that's probably out-of-sync.