Every Chromebox runs Linux.
But now Google has improved the process so you can basically just flip a switch and use the underlying Linux [0] [1]. It's kind of like WSL, but to me it feels like 100% Linux.
[0] https://www.pcmag.com/how-to/install-linux-on-your-chromeboo...
[1] On Intel Chromebooks. For ARM Chromebooks, you still need to dual-boot to get something that feels like "real" Linux. [2]
[2] Which is kind of ironic given that ChromeOS can run Android apps now, and Android apps are ARM based [3], so they have to be run in emulation mode on Intel CPUs.
[3] Okay they're bytecode based. Android apps on Intel Chromebooks used to run the JVM in emulation mode (I think) but there may now be a native Intel version of Dalvik or whatever-Google-calls-their-JVM-these-days.
Well worth it though, especially if you max them out on RAM after installing Linux and you can get them for little money as 'bricked' for instance out of contract dedicated Google Meet hardware.
IMO it's beside the point. Calling ChromeOS "Linux" is like calling cells "mitochondria". One could argue that the same could be said about the somewhat standard Linux desktop stack you'd find on Ubuntu or Fedora installs, and that's true. However, that's probably mostly just a consequence of the fact that Linux doesn't have an actual standard userspace. The closest it has is the defacto set of components you're likely to find in any GNU/Linux distro, and they are quite different than what you'll find when you boot up ChromeOS or Android.
However, it's important to note that Linux on this device is subject to certain restrictions: It operates within a containerized environment, which limits both disk space allocation and system-wide access. Accessing the terminal requires navigating through a "virtual machine", and files are shared within the /mnt/chromeos directory. Additionally, the utilization of USB devices is layered behind the primary operating system support and Linux backups are separate from the overall operating system backups.
If you want uncontainerized Linux you have to dual-boot. I used to do that but it's difficult and no longer worth the hassle IMO.
1. Yes, ChromeOS is based on Linux, but it's not really what most people would refer to as "Linux". I think this is what you're talking about.
2. ChromeOS does have, however, some great technology to run an unrestricted version of Linux in a container, called Crostini: https://chromeos.dev/en/linux . I used to use a high end Pixel book (which was a great machine, really sad Google discontinued it - surprise, surprise, I know) as a primary dev laptop, it ran VSCode, postgres, etc. very well.
Crostini is a VM, and isn't 100% unrestricted. I'd classify it in the same category as WSL or Parallels.
At that point, as you poke around, you find that chrome os is actually built on top of gentoo Linux.
And there is a 3rd party pkg manager (chromebrew) which gives you gcc, and thus a whole host of additional pkgs.
Yup, its linux all right. Even without going the crouton (chrome into another distro) or crossing (vm running separate linux distro) route.