As a researcher, I care for being open with knowledge and code. It makes the world a much better place, where we can use programs freely and look into implementations of complete strangers to understand algorithms or APIs. Over the years, I've been working on different projects either just for fun or because they were related to my work:

• Key Promoter X is a small plugin for IntelliJ IDEs that helps users to learn keyboard shortcuts by displaying small notifications when buttons are clicked with the mouse. It's top-rated and has more than half a million downloads.
• I wrote the official highlighter for Wolfram Language code that is used on StackExchange and the official Wolfram Community. I also ported this to Rouge which is (one of) the highlighters that can be used with Jekyll.
• I teamed up with Albert Rich to work on Rubi, a package for rule-based integration to find the antiderivatives of symbolic expressions which outperforms the big computer algebra systems in many cases. Also, I helped to port this to Symja, an open-source CAS.
• I released several packages related to my work for importing Optical Coherence data, doing Color Deconvolution, and analysing foveal shapes.
• I maintain the additional StackExchange buttons and the Mathematica SE Tools which are small but highly appreciated tools for the users of the Mathematica StackExchange site.

Besides the repositories on GitHub, I'm a high-reputation user on the Mathematica StackExchange site where I provide solutions to many answers and share my knowledge freely.