Hey LOR!
Mesosphere is an open source kernel version of the Horizon operating system for the Nintendo Switch that is compatible with the original. Developed by Atmosphere custom firmware author and development team. At the moment, the kernel is loaded and running on the console, games also work. However, there are still a large number of bugs and missing features.
The source code is published under the GPLv2 license with exceptions.
Source: linux.org.ru