> He meant to build an efficient tarball history database toolset, not really a version control system. He assumed that someone else would write that layer.
Famous last words: "We'll do it the right way later!"
On the flip side: when you do intend to make a larger project like that, consciously focusing on the internal utility piece first is often a good move. For example, Pip doesn't offer a real API; anyone who wants their project to install "extra" dependencies dynamically is expected to (https://stackoverflow.com/questions/12332975) run it as a subprocess with its own command line. I suspect that maintaining Pip nowadays would be much easier if it had been designed from that perspective first, which is why I'm taking that approach with Paper.