[vocworker]

dpkg-reconfigure is really important and maybe a bit outdated, but definitely something users should know? I think it's also responsible for turning 'apt upgrade' into a little text adventure, e.g. by showing lots of prompts like "Do you want to replace/skip your sshd config"?

[jbverschoor]

It's better to use configuration / override directories such as sshd_config.d/ to specify customizations.