Maybe in addition to integration and generalisation, reliable code maintenance could be something I could practice, too.

A great example for that would be the android pull request I have open for libusb. It badly needs a maintainer as more people use it, and it doesn't have its changes ported forward as the main tree progresses.

One challenge when maintaining from limited capacity, is how much feature addition and refactoring to do. The primarily challenge is defending stability of the software without compromise.