Chromebooks run ChromeOS, which is based on the Linux kernel, not Windows. While designed to be a lightweight, secure system primarily for web apps, modern Chromebooks can run Android apps and have built-in support to run standard Linux desktop applications.
Key details:
Operating System: ChromeOS is built on Gentoo Linux.
Linux Support: You can enable a "Linux (Beta)" environment (Crostini) to install Linux applications.
Windows Apps: They do not run Windows natively, though web-based alternatives or virtualization can be used.
Functionality: They are designed for speed, security, and cloud-based tasks, rather than heavy local processing.