At first glance, these tools seem to be a bit behind the likes of GitHub Pull Requests combined with any number of the great review tools out there. Not to say reviewers at Google aren't doing quality work, and ultimately the tool itself doesn't matter as much as people think, and I don't see any special sauce here.<p>A lot of big tech companies have developed totally in-house tools and procedures for basic software development that mirror, but aren't quite the same as, widespread industry practice.<p>Before the Google Way of doing things, there was the Microsoft Way. Before that, there was the IBM Way, etc.
If you want to read about the process and not the tooling, go straight to the paper mentioned in the article: <a href="https://research.google/pubs/modern-code-review-a-case-study-at-google/" rel="nofollow">https://research.google/pubs/modern-code-review-a-case-study...</a>