The top external contributor is the maintainer for QtCore, Thiago Macieira (from Intel). He used to have great statistics about Qt contributors on his website,

The top external contributor is the maintainer for QtCore, Thiago Macieira (from Intel). He used to have great statistics about Qt contributors on his website, although it seems to currently be down. https://www.macieira.org/blog/qt-stats/ https://www.macieira.org/blog/qt-stats/