Managing repositories and signatures with yum/dnf

RHEL, like many other Linux distributions, has a mechanism to provide software based on repos. These contain a list of software packages (which could be end user applications such as Firefox, or components for them such as GTK3), a list of dependencies between the packages, and other useful metadata.

Once we finish subscribing the system, we can take a look at the repositories available in the system using yum or dnf:

[root@rhel-instance ~]# yum repolist
Updating Subscription Management repositories.
repo id                              repo name
rhel-8-for-x86_64-appstream-rpms     Red Hat Enterprise Linux 9 for x86_64 - AppStream (RPMs)
rhel-8-for-x86_64-baseos-rpms        Red Hat Enterprise Linux 9 for x86_64 - BaseOS...