Haiku
https://www.haiku-os.org/Haiku is an open-source operating system that specifically targets personal computing. Haiku is fast, simple to use, easy to learn and yet very powerful.
Haiku is named after the classical three-line Japanese poetry form. Haiku poetry is known for its quiet power, elegance and simplicity - among the core qualities of BeOS which we aim to recreate in Haiku. BeOS included some haiku in its user interface, in the form of network error messages displayed by its web browser.
While Haiku is still in Alpha stage and has no official stable release, another goal for the project is to share knowledge about operating system development, with a clean code base and a community ready to help newcomers learn how things are done.
Primary Open Source License: MIT license (MIT)