KDE neon is downloadable as a LiveCD with an installer, it shows as "neon Linux" in the bootloader, and you use
pkcon rather than
apt as a package manager.
You could add the repos yourself to Ubuntu and have something very similar, but the way it is distributed, it is absolutely a distro.
It is certainly not the official, canonical KDE distro in any way, it is just a good distro with phenomenal KDE integration.