It turns out that when I prepared a certain Raspberry Pi several months ago, I used the full Raspbian image. Since then, that Pi is on headless duty just running some server software. When I run updates on it, a whole lot of stuff I'll never use gets updated. Migrating from jessie to stretch took unnecessary hours.
What can I do to move to the lite version from within the existing installation?
I would presume that I can remove some package and install another, like the ubuntu-desktop on Ubuntu, but what would that be on Raspbian?