This is a fantastic post on the challenges associated with diving into large codebases (sometimes called "source diving" or "code archaeology"). The vast majority of code in the world is in large private codebases. The size of legacy private code dwarfs that of the open source world (sizable as that might be these days) and the rate at which you can read/understand code is the limiting factor here for dev velocity.

Some companies have invested in dedicated tools (like Code Search and Grok at Google) because they recognize the importance of the problem. Such systems were a primary source of inspiration for us when we started Sourcegraph—we wanted to bring the tech for large-scale code understanding to every company. In-depth posts like this are a big source of inspiration and ideas for us, so thanks to the author for writing this up.