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.
The two timezone files are now installed in the global setup. I am not too
happy about this, but it still seems better than to create a completely
separate image just for this.