debian is an operating system and a distribution of free software. it is maintained and updated through the work of many users who volunteer their time and effort.
red hat is the world’s leading provider of enterprise open source solutions, including high-performing linux, cloud, container, and kubernetes technologies.
ubuntu is the modern, open source operating system on linux for the enterprise server, desktop, cloud, and iot.
KDE is an open community of friendly people who want to create a world in which everyone has control over their digital life and enjoys freedom and privacy.