Introduction
“The Chromium Projects” include the open source projects Chromium (the project behind Google Chrome browser) and Chrome OS (behind Google Chrome OS).
About

It was initially developed by Google and made available open source to be contributed on by the community.
Anyone can contribute to the chromium and chromium os projects – even you!
Not only that, you can even develop your own browser or operating system starting from them. You just have to read carefully the open source license.
License
As quoted from the official site:
Except as otherwise noted, the content of this page is licensed under a Creative Commons Attribution 2.5 license, and examples are licensed under the BSD License.
https://www.chromium.org/chromium-projects/