Those are all consumed by our parser, so they all support comments.
I was considering whether they should have a license header at all,
but in the end I decided to add it because those files are often created
by copying parts of real unit files. And if the real ones have a license,
then those might as well. It's easier to add it than to make an exception.
It's hard to trigger the failure to exit the rate limit state in
isolation as it needs multiple event sources in order to show that it
gets stuck in the queue. Hence why this is an extended test.