The paper's conclusion that "women are more competent overall" doesn't seem very plausible to me. If there was really a significant, consistent boost simply from being female then we'd see software companies that consist mostly of women or which are run by women outcompete opposite companies at least some of the time, and it'd be an effect that'd have been detected before. I'm struggling to think of any examples of this.
Based on my own experience of github and open source, however, the only times I have ever seen women contribute to open source, they were always being paid to do so. I cannot recall a single time that I came across a pull request or even just a regular patch from a hobbyist woman. Not sure why that is, but it has been a constant throughout my career - men do hobby programming and women don't.
Given this difference I'd expect contributions from women to be larger overall, tackling grunge work that volunteers wouldn't want to do, solves some real business problem, and more frequently be code that was tested for a while internally first so is less likely to have quality problems.
The fact that men are also less likely to have pull reqs accepted when their gender is known also seems likely to be a correlation with submitting from personal gmail accounts vs corporate accounts.