Re: prevent packages from installing
> The man page for apt_preferences is clear as mud about any (pinning) example
> that seems equivalent, or even what name(s) of file(s) are supposed to be to
> create pins. Google so far has been no help. Holding is either being ignored, or
> holds are being silently unheld. How do I keep unwanted packages from getting
> apt purge xserver-xorg-video-radeon
> Attempting to do so wants to install
> The only driver I want used is the modesetting driver built into the server.
> Anything else for this installation I would consider broken.
Check if apt-mark does what you need.