• {fmt}: a modern formatting library for C++ (author)

• Facebook Thrift: a serialization and RPC framework for service communication

• AMPL/MP: an open-source library for mathematical programming (a former maintainer)

• schubfach: a C++ implementation of the Schubfach algorithm - fast and accurate conversion of IEEE-754 double values to decimal strings

• modules: simple C++20 module support for CMake

• Breathe: reStructuredText and Sphinx bridge to Doxygen (a former co-maintainer)

Open-source contributions on GitHub.