Which distribution is known as the most popular derivative that is based on Debian?

Ubuntu is recognized as the most popular derivative of Debian. This popularity stems from its user-friendly interface, comprehensive community support, and a regular release cycle that includes Long Term Support (LTS) versions, which are well-received for their stability and reliability.

Ubuntu builds upon the Debian architecture, inheriting its stability and extensive package management system. It also introduces features that enhance usability, catering to both new users and experienced professionals. This has made Ubuntu the go-to choice for desktops and servers alike, further increasing its adoption in both personal and enterprise environments.

Other choices, while they have their own niches, do not carry the same level of popularity as Ubuntu in the broader community. Fedora, for example, is known for its cutting-edge features and ties to Red Hat, which positions it differently from Debian-based derivatives. OpenWrt is specialized for embedded devices and networking, while Kali Linux is focused on penetration testing and security assessments. Thus, their audiences are more targeted and don't match the general appeal and widespread usage of Ubuntu.