New warning upon enablement of display manager services

Description:

Heads up for latest systemd-256-3. Anyone else seeing this?

When any of the usual display managers (lightdm, gdm, sddm) are enabled with systemctl, a rather disconcerting warning message is displayed:

$ sudo systemctl enable lightdm
Created symlink '/etc/systemd/system/display-manager.service' → '/usr/lib/systemd/system/lightdm.service'.
The unit files have no installation config (WantedBy=, RequiredBy=, UpheldBy=,
Also=, or Alias= settings in the [Install] section, and DefaultInstance= for
template units). This means they are not meant to be enabled or disabled using systemctl.
 
Possible reasons for having these kinds of units are:
• A unit may be statically enabled by being symlinked from another unit's
  .wants/, .requires/, or .upholds/ directory.
• A unit's purpose may be to act as a helper for some other unit which has
  a requirement dependency on it.
• A unit may be started when needed via activation (socket, path, timer,
  D-Bus, udev, scripted systemctl call, ...).
• In case of template units, the unit is meant to be enabled with some
  instance name specified.

It seems suspicious that all 3 display managers are affected. Upstream systemd issue? All 3 service files need to be fixed? Does anyone know what's going on here? I'm having trouble parsing the first sentence 🤔