See what landed recently in Firefox Nightly!

Starting with Firefox 154, Firefox Nightly is testing a simpler tab context menu in Firefox Labs. It can be turned on in Settings > Firefox Labs > Streamline tab menu, and feedback is welcome on Mozilla Connect.

Starting with Firefox 154, Firefox Nightly now supports QUIC version 2 (RFC 9369) for HTTP/3 connections. Firefox offers both QUIC v1 and v2 using compatible version negotiation (RFC 9368). The server selects which version is used, so connections upgrade to QUIC v2 when the server chooses it and remain on QUIC v1 otherwise.

Starting with Firefox 155, the RegExp Buffer Boundary proposal is now available for testing in Nightly builds by setting the javascript.options.experimental.regexp_buffer_boundaries preference.

Starting with Firefox 155, Firefox Nightly offers limited support for the Speculation Rules API for same-origin prefetch, allowing pages to declare which links should be prefetched. This initial support covers only the immediate eagerness level and list source rules.

Starting with Firefox 155, Nightly builds enable the Audio Session API, letting sites declare how their audio mixes with other applications.

Starting with Firefox 155, Nightly builds now support the at-rule() function for @supports. This allows authors to test for browser support of specific at-rules, such as @supports at-rule(@scope).

Starting with Firefox 155, Firefox Nightly supports typed arithmetic in CSS calc(), allowing units to be multiplied and divided within math functions.

Starting with Firefox 155, Firefox Nightly supports the <a> element in the MathML namespace, exposed via the new MathMLAnchorElement WebIDL interface, so mathematical expressions can be links.