Zepyhr comes with the Apache 2 license so that corporations that shy away from GPL can use it.
Many companies do not want to share the changes they add to the OS in these spying times - including industrial spying: the Apache2 license takes care of that.
Zephyr is a new OS not based on Linux even if the Linux Foundation is pushing it
The Linux Foundation is the organization of choice for the world's top developers and companies to build ecosystems that accelerate open technology development and commercial adoption. Together with the worldwide open source community, it is solving the hardest technology problems by creating the largest shared technology investment in history. Founded in 2000, The Linux Foundation today provides tools, training and events to scale any open source project, which together deliver an economic impact not achievable by any one company.
Some of the companies behind Zephyr are :Intel, NXP Semiconductors and Synopsys.
The Nano kernel does one thing at the time and requires few resources.