What the heck is a 16mm negative film for?

[TV-collector]

Hi Folks!

Somebody who works for the bavarian TV gave me some stuff for my
collection!
There are two metal film cases showing the ownership with a nice logo.
One case is empty, signed with "Positiv Film".
The other one is signed "Negativ Film" and is covering a negative film.

As I remember right a film is always after bathing a positve film which can
be used for home cinema (8mm, Super 8mm, 16mm 35mm) or am I wrong?

For what reason a TV station used negative films?

May I can turn the video signal of this film after it comes out of the film
player (Fernseh GmbH) to watch this film?
Until now I am not clear about the sound of the film, magnetic line or
light sound.
I like to watch/restore that original television film!

Any ideas?
Many thanks in advance!
TV-collector