On my Mac's, using Safari, located in the lower left-hand corner of the browser window there is a button on every ECF page to toggle the width.
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I saw you are using Safari in your previous post about playing FB videos.
FWIW, if you go into Safari settings, choose Privacy, then select "Prevent cross-site tracking", that setting will prevent Facebook (and other sites) from tracking you online. My iPhone, iPad and Mac's are all setup to prevent cross-site tracking. I was able to play the Roger Waters video without getting the message you got (your screenshot).
Apple implemented that change in 2018 with macOS Mojave.
The next versions of the iOS and the Mac operating systems will block the social network's trackers.
www.bbc.com