[core2]

Mate, the option, when you enable it - it's disables all ads and tracking from Google and some other networks.

It's doesn't matter on what network you are, on what device.

I'm on desktop dual Xeon, with high bandwidth, and this feature disables Adsense ads. It's not disable some other Ad networks, for which Mozilla never heard of, but most of the Ads are disabled.

"No they are not modifying your code at all."

Content is modified, some ads are stripped away.

[keithpeter]

The adverts are not your content. You do not know what adverts will be seen by viewers to your page. That (if my understanding is correct) is determined by the algorithmic tracking of users. The adverts may be completely irrelevant and distracting from your content.