The video shows how to install the Flathub repository on Ubuntu. The instructions will work on the main version of Ubuntu and the official derivitives, such as Kubuntu, Xubuntu, and UbuntuMATE
For those who want to know how to install the Flathub repository on other distros that don't come with it preinstalled, here are two Websites:
https://flatpak.org/setup/
https://oscollege.com/install-libreof...