You didn't happen to look at those files? main.cpp is 8900 lines, dialogs.cpp something almost as long. It's probably super performant but I wouldn't volounteer to maintain that codebase unless getting paid (And the commit history only shows the author...)
That's nice until it breaks down, besides doesn't help much if you have 2400 lines long functions ( cbMainWindow ) that mixes Win32 API drudgery with indentation logic and SQLite fiddling.
Sure it's an cute and to-the-point codebase, but even if I have experience with using these API's I'd never volunteer to work on this codebase because it's obviously also one that's a creation of the authors memorized experience.