I feel sort of odd never having installed an ad blocker, but firefox must do some stuff also because a few websites still complain and tell me to turn it off, whatever "it" is. I'm pretty good with the youtube skip button does that count?
Likely referencing Firefox's enhanced tracking protection.
You can control it with the lil purple shield icon to the left of the address bar (not that you're obliged to disable it for some website just because they asked, of course!)
https://support.mozilla.org/en-US/kb/enhanced-tracking-prote...