Google is also a very good learning opportunity; there is lots of training available to employees, you will be working with very talented people, and will get to see how the planet-scale dogfood is made first hand.
Just like any other successful company that does something interesting and has been around more than a couple of years.
Borg is Kubernetes, flume is externally available as Google Cloud Dataflow (it's basically Apache Beam), Tensorflow is open source, many of Google's internal java libraries and tools are available externally (Guava, Guice, Dagger), and absl (c++ common libraries) are also available externally.
More importantly, assuming you land on a team with strong software engineering culture (this is likely, but admittedly not guaranteed, even at Google), the general skills you pick up for software design, planning, testing, etc. are transferable anywhere.
That said, all of this applies mostly to software engineers. If you're applying for an SRE position, then I've heard the experience is less transferable, but it's not something I could comment on first hand.
When I left Google for a startup, all the tools I took for granted didn't exist. But because I knew how things could and should work, I was able to apply open source and commercially available tools to improve software development practices at my new employer.
Also, Google's best tools are increasingly open-source.
Do you think they are more talented than other companies, like, say, Amazon?
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Amazon isn't really particularly good at any of these, so you'll tend to find more talent at places that do better. Facebook and Google both have better compensation and from what I've heard from friends (who've also had experience with Amazon), both also have a better working environment.