I just became aware of the fact that there was a resolution back in 2022 which results in a new component for APT packages.

I currently run on Debian unstable - which is rather stable - and have the following entry in my /etc/apt/sources.list:

deb http://http.us.debian.org/debian/ unstable main contrib non-free

If you want to access firmware packages (including upgrades), you'll have to add non-free-firmware. So, my updated list entry now looks like this:

deb http://http.us.debian.org/debian/ unstable main contrib non-free non-free-firmware