GNU/Linux Ubuntu 20.04 GNOME Sushi 3.38 Source Installation Guide
How to Install GNOME Sushi 3.38 from Source Code and so Add QuickLook macOS Style to the GNOME Nautilus File Manager in Ubuntu 20.04 Focal LTS GNU/Linux desktop.
And Gnome Sushi for Ubuntu Focal is a quick previewer for Nautilus, the GNOME desktop File Manager.
Especially relevant: the gnome-sushi 3.34 previewer is Not Working on GNOME 3.36+ and so currently the Source setup is the only available Solution.
Finally, this guide includes detailed instructions on Getting Started with GNOME Sushi File QuickLook on Ubuntu.

1. Terminal QuickStart
How to QuickStart with Command Line on Ubuntu
First, Update the Apt Repo Sources with:
sudo apt update
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