I just came across this example for the user friendly redesign of a tool, piper, which allows users to configure gaming mice (with sometimes elaborate functionality).
Design-wise, the sections on the buttons-page and the welcome screen are most interesting.
It also is an example for the principle, that design changes in open source projects are easiest/most likely to succeed if one does design and code, as the coder/designer in this project. (Which @htietze once described to me as design in open source is DIY and which fits some of the problems of open source design. )