In case you want to find out how to locate the actual, unlisted videos from #advertisements on #YouTube:
1.
right click on the playing ad and select "copy debug informattion".
2.
open up a text editor and paste that in.
3.
search for the addebug_VideoID
and add https://www.youtube.com/watch?v=
before that.
4.
You get the Video-URL (i.e. https://www.youtube.com/watch?v=J8J4icxoF0M
).
You're welcome, folks!