I invented the Python bits of the Firefox build system (moz.build files). I learned after I implemented them that Google's internal approach with Blaze was very similar. It felt reassuring that I independently reinvented a similar solution :)

There are a handful of Blaze derivatives built by Xooglers. Pants and Buck come to mind. They also share the trait of using sandboxed Python to define a build configuration. I'll take it over make syntax any day!