Niklas Gögge and Christoph Kerschbaumer July 12, 2021 We are pleased to announce that Firefox 90 will support Fetch Metadata Request Headers which allows web applications to protect themselves and their users against various cross-origin threats like (a) cross-site request forgery (CSRF), (b) cross-site leaks (XS-Leaks), and (c) speculative cross-site execution side channel (Spectre) attacks. Cros