/nIn vTmkB66N, Diesel
wrote:

When I'm using the plugin to leech a specific video, it doesn't include
the slipstream advertising because youtube isn't 'streaming' the video
to me at this point and has no control over the process. Instead, it
established a direct download link and is pulling the video/audio file
I wanted. So, there's nothing for youtube to pause and swap out on me.
The only way youtube could get around that would be to actually embed
the advertising into the original video, and, since alot of videos have
different formats and quality options, they'd have to do it to all of
them. Wasting storage space and processor resources on their end. I
don't see them intentionally doing that anytime soon.

This explanation above advances our tribal knowledge quite nicely, where it
may explain why New Pipe and the Youtube downloader work, even though
Google has known about them for years and their source code is wide open to
inspection by Google.