Google stealthy published source code of a new operating system at its own code depository as well as on GitHub. The only description given by Google is a rather cryptic message stating that Pink + Purple == Fuchsia (a new Operating System).
One important difference versus Google's other operating system like Android and ChromeOS is that Fuchsia is not based on Linux. An investigation of the source code reveals this operating system is based on the Magenta microkernel, that is itself based on a project called LittleKernel.
The code is designed to be lightweight and seems to be designed for embedded systems, Internet of Things applications and perhaps even augmented reality interfaces:
However, the Magenta kernel can do a lot more than just power a router. Google's own documentation says the software "targets modern phones and modern personal computers" that use "fast processors" and "non-trivial amounts of RAM." It notes that Magenta supports a number of advanced features, including user modes and a "capability-based security model." Further evidence that Fuchsia is intended for more than just Wi-Fi-connected gadgets include the fact that Google already has its own IoT platform (the Android-based Brillo), and the fact that the new OS includes support for graphics rendering. Some users of Hacker News have even suggested that Fuchsia could be use for augmented reality interfaces. (Google itself has yet to respond to requests for comment.)
It's unknown if this is just a research project or whether Google has big plans for Fuchsia. Further details at The Verge.