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Firefox 160: Desktop On-Device SpeechRecognition in 40 Languages, an Early-Version Mini Window; MDN Says a WebTransport Change Needs Code Updates

Mozilla's Firefox 160, released November 10, 2026, supports on-device SpeechRecognition on desktop in 40 languages and adds an early-version Mini Window; MDN lists WebTransport changes.

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firefox mozilla web-speech-api webtransport browsers
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Overview

Mozilla released Firefox 160 on November 10, 2026, according to its release notes and MDN’s developer notes. The release adds a Mini Window feature that Mozilla calls an “early version” and a “Never allow” button for sites that repeatedly ask to handle mailto: links. For web developers, MDN lists on-device speech recognition through the Web Speech API on desktop, several WebTransport changes, and a new CSS alias. LWN.net, OMG! Ubuntu and heise online each reported the release, and their feature lists differ in places, as noted below. An earlier Herald article covered Firefox 159.

Speech recognition

Mozilla’s release notes say the SpeechRecognition interface of the Web Speech API is now supported, “providing on-device, real-time speech-to-text in 40 languages.” MDN’s developer notes give the scope: the feature is “now available on desktop,” and “Recognition is not supported on Android, and neither is remote (cloud) recognition.” The firefox.com release notes do not state the desktop-only scope.

MDN’s guide to the Web Speech API describes how pages ask for on-device processing. A page sets the processLocally property, which defaults to false, to true. The guide says on-device recognition requires a one-time language pack download for each language, after which it is available offline. If processLocally is true and the language pack is missing, start() fails with a language-not-supported error, and pages can check for packs with SpeechRecognition.available() and install them with SpeechRecognition.install(). According to the guide, the on-device-speech-recognition Permissions-Policy, whose default allowlist is self, controls those two methods. The guide describes the API generally and is not specific to Firefox.

heise online says users “must first download an AI model for recognition” and that recognition afterwards works without an internet connection, with the website receiving the recognized text. MDN’s guide calls the download a language pack; neither source explains the difference in wording. As of November 13, 2026, MDN’s SpeechRecognition reference page carries a “Limited availability” label and says the feature is not Baseline because it does not work in some of the most widely-used browsers.

WebTransport and other platform changes

MDN’s developer notes list these changes, among others:

  • WebTransport: the WebTransport() constructor accepts a headers option that adds custom HTTP headers to the extended CONNECT request, and the server’s response headers are available in WebTransport.responseHeaders. The constructor also supports a datagramsReadableType option; set to bytes, it makes the incoming datagram stream a readable byte stream.
  • A change MDN says needs code updates: WebTransport.exportKeyingMaterial() now requires a context argument and takes a new outputLength argument; previously, MDN says, the method always returned 32 bytes. MDN says code that omits either argument will need to be updated.
  • Renamed buffering properties: incomingMaxBufferedDatagrams and outgoingMaxBufferedDatagrams are supported and replace the non-standard incomingHighWaterMark and outgoingHighWaterMark, which MDN says have been removed.
  • CSS: ::-webkit-input-placeholder is supported as an alias of ::placeholder, which Mozilla’s release notes say is meant to improve compatibility with sites that use it.
  • Removal: the non-standard MozScrolledAreaChanged event is no longer dispatched to web pages; setting the layout.scrolled-area-changed.content.enabled preference to true restores it.
  • Extensions: runtime.PlatformInfo now returns arm64 rather than aarch64 for ARM64 platforms, which MDN says aligns Firefox with Chrome.

MDN also lists five features that ship in Firefox 160 but are disabled by default (the count is the Herald’s, from the page’s headings): render blocking, lazy loading for video and audio, the Speculation-Rules header, CSSNumericValue arithmetic methods, and the Canvas 2D colorSpace option. MDN says the header is enabled by default in Nightly and the arithmetic methods are supported in Nightly. For the canvas option, MDN says pixel data is not yet converted between color spaces, so getImageData() returns the same pixels whichever color space is requested.

Browser features

The release notes describe Mini Window as moving “a tab or a selected part of a page into an always-on-top window while browsing” and ask for feedback on “this early version of the feature.” LWN says it is “in early development,” while OMG! Ubuntu says it “is in beta.” OMG! Ubuntu describes opening it from the tab context menu or the toolbar, and heise online gives a dashboard section kept visible while working in other tabs as an example.

The release notes also list a Picture-in-Picture playback speed setting from 0.25x to 2.0x that appears only when the player window is medium-sized or larger; a “Never allow” button for sites that repeatedly ask to handle mailto: and other links; playback of Matroska (MKV) files with FLAC, MP3 or PCM audio; and WebGL rendering through Apple’s Metal API on macOS, which Mozilla says “can improve performance on some sites.” Other entries cover dragging history entries to the tab strip, a “Paste and Search” menu label, MathML accessibility in saved PDFs and Organize Tabs in French for Smart Window, which the notes say is part of a progressive roll out. Fixes include a freeze of several seconds when signing in to intranet sites using NTLM or Kerberos authentication. The notes also list “Various security fixes”; this article does not assess them.

Where the accounts differ

OMG! Ubuntu’s list of other changes includes “US users can now access the Yahoo! Scout in the chatbot sidebar.” The en-US and en-GB release notes and MDN’s developer notes, as read on November 13, 2026, contain no mention of Yahoo or Scout, and neither does LWN’s brief or heise online’s article. The sources do not explain the difference, and the Herald could not confirm the item.

What the sources do not say

None of the cited sources says when Mini Window will move beyond its early stage, or what a page that does not set processLocally experiences in Firefox 160, where MDN says remote recognition is not supported.