So where is that paragraph found on their website?
The relevant section isn't what you linked to - scroll down to the change in structured-data-firefox-faq.html
Here is the previous version of the FAQ: https://web.archive.org/web/20250128115051/https://www.mozil...
Here it is now: https://www.mozilla.org/en-US/firefox/faq/
All three statements about not selling your personal data are gone.