Unclear to me are what these headers do to the browser. I mean... the docs say that they are a "site" header that you should apply to a "page". Does that mean

Unclear to me are what these headers do to the browser. I mean... the docs say that they are a "site" header that you should apply to a "page". Does that mean that you must apply it to all pages to exclude a site? Is absence on one page taken as opting back in to FLoC? If the scope is site, then it would be better as a DNS entry. I've a feeling the scope is truly page though and I've also a feeling that most people who choose to add this header will add it on all assets now - which is a bit of a waste of bytes (even with header compression in place) but would be the only way to guarantee that all pages have it.