Note that google3 is a subset of the entire Google codebase. But it still contain more than half of its code (>2B LoC), mostly those running over their cloud. I

Note that google3 is a subset of the entire Google codebase. But it still contain more than half of its code (>2B LoC), mostly those running over their cloud. In contains all the infrastructure code as well, including Linux kernel, compiler, tool chain... literally everything needed. When you build some big binaries, you may see more than 500k~1M build targets analyzed and built (or pulled from cache).