systemd clarification

[Mike Jones]

I would like to clarify some systemd behavior.

Related to:

/etc/systemd/system
/lib/systemd/system

The lib path is not a search path in the systemd documentation, and the etc path has links into the lib path. So I assume services in the lib path are only run if they are linked into the etc path. Is this correct?

If there is a an After= that lists something found only in the lib path, I assume it will run because After is not strong enough to prevent start. But if it was Requires=, then I assume it cannot start unless it is linked into the etc path so that it is available. Is this correct?

I just want to be certain systemd was not modified or configured in a way to run things from lib directly.

Mike