New review comment by subnut on void-packages repository

https://github.com/void-linux/void-packages/pull/41919#discussion_r1097759875

Comment:
Ah, I see it's mentioned in `Manual.md`

> If the package installs a systemd service file or other unit, leave it in place as a
reference point so long as including it has no negative side effects.

But I still don't understand. What does it mean by _reference point_?