The thread does not explain whether the behaviour of Firefox was actually changed when they added the check box, or if it is a new option to opt-out of something that could not be opted-out before.
> Firefox now supports the experimental Privacy Preserving Attribution API, which provides an alternative to user tracking for ad attribution. This experiment is only enabled via origin trial and can be disabled in the new Website Advertising Preferences section in the Privacy and Security settings.
https://www.mozilla.org/en-US/firefox/128.0/releasenotes/
This is the page users saw when they updated to 128. No mention of this setting.
https://www.mozilla.org/en-US/firefox/128.0/whatsnew/?oldver...
> Firefox now supports the experimental Privacy Preserving Attribution API, which provides an alternative to user tracking for ad attribution. This experiment is only enabled via origin trial and can be disabled in the new Website Advertising Preferences section in the Privacy and Security settings.
> I recommend turning it off, or switching to a more privacy-conscious browser such as Google Chrome.
Which seems an interesting comment from someone so extremely anti-advertising.
"Now to be clear, the disclosure Chrome provides to users is not adequate. Their wording of the "Ad Privacy" feature popup is highly disingenuous and the process to disable once notification is given is too complex and must be performed on a per-profile basis. But at least they do it"
It is located at "Settings" -> "Privacy & Security" -> "Website Advertising Preferences" and is checked by default.
Boolean dom.private-attribution.submission.enabled False
It disabled the checkbox after updating Firefox. I set it to true to test and it enabled the checkbox also.