Ask HN: What open-source projects are you looking at?

I have found reading code is a good way for me to improve my skills. I am looking at Mattermost[1] and Spectrum[2] to improve my React.js.

What open-source projects are you currently looking at?

[1] https://github.com/mattermost/mattermost-webapp [2] https://github.com/withspectrum/spectrum