Bazzite (Fedora atomic): install virtualbox on Bazzite custom image

Bazzite has rpm fusion repositories added in /etc/yum.repos.d/. However, even though they are enabled, by default you can't install any packages from them. You can force the use of the RPM repo as follows:

sudo dnf --enablerepo=rpmfusion-free install virtualbox
This will still NOT install the virtualbox in atomic fedora as its read-only system. But can be useful for building custom atomic images which would contain the virtualbox or other packages.

Example of how the virtualbox can be installed in a custom image of Bazzite is here:
https://github.com/ettfemnio/bazzite-virtualbox