Specifying Repository for Driver Installation on Ubuntu

Summary: I am trying to install the xf86-video-fbdev driver (https://archlinux.org/packages/extra/x86_64/xf86-video-fbdev/) on Ubuntu 20.04 using sudo apt-get install xf86-video-fbdev as suggested by this (https://opensource.com/article/18/11/how-install-device-driver-linux) article. Unfortunately, I am getting an error: E: Unable to locate package xf86-video-fbdev. I suppose this is because I am not specifying a repository in which to look for this package. The command to add the repository in the above article contains a parameter REPOLIST_OF_DRIVER, for which I do not know what to use. How can I find what to use for this parameter?

More background: I have a Mid 2010 21.5" iMac on which I am trying to install Ubuntu 20.04 (single boot). According to the ArchWiki page, this particular model has some issues with linux which I was not aware of when I first started trying this install (https://wiki.archlinux.org/title/IMac_(21.5-inch,_Mid_2010)). So, I am trying to follow the instructions at this ArchWiki link to install the xf86-video-fbdev and xorg-xrandr drivers and then write the specified script. As laid out above, I am running into issues with installing these drivers.

I would highly appreciate clear and detailed suggestions, since I am not very adept at understanding computers. Thanks in advance for any help!

xf86-video-fbdev is an Xorg driver for framebuffer devices. There is no official xf86-video-fbdev package available for Ubuntu 20.04 and no PPA that contains the xf86-video-fbdev package, but there is xf86-video-fbdev source code at GitLab and xf86-video-fbdev is in the official openSUSE repositories.

xserver-xorg-video-fbdev provides the driver for the Linux framebuffer device (aka 'fbdev'). To install this graphics driver on all currently supported versions of Ubuntu open the terminal and run the following commands.

sudo apt update
sudo apt install xserver-xorg-video-fbdev
sudo reboot