Firefox 160: one quiet breaking change and a few useful experiments
WebTransport headers, on-device speech-to-text, and one change to check.
Firefox 160 reached the stable channel on 10 November 2026. It is a small release for most websites, but it carries one change that can break existing code.
Check this first
exportKeyingMaterial() in WebTransport now follows the latest spec: the context argument is required and there is a new outputLength parameter. Code that called it without both arguments needs an update. If you do not use WebTransport, you can skip this.
What is new
- CSS:
::-webkit-input-placeholdernow works as an alias of::placeholder, so older stylesheets render the same in Firefox. - WebTransport: you can send HTTP headers when opening a session and read the server's reply headers.
- Web Speech API: speech-to-text can run on the device on desktop, in 40 languages. Android is not supported yet.
Worth watching (off by default)
Render-blocking blocking="render", lazy loading for <video> and <audio>, a Speculation-Rules header, arithmetic on CSS Typed OM values and a display-p3 colour space for canvas are all behind flags in about:config. Lazy-loaded video in particular would help portfolio pages like ours that lean on heavy media.