Firefox 154 release notes for developers (Beta)

Changes for web developers

APIs

Media, WebRTC, and Web Audio

• The RTCIceTransport.getSelectedCandidatePair() method and selectedcandidatepairchange event are now supported for getting the current RTCIceCandidatePair for the transport. (Firefox bug 2019332).
• The error event is now fired on RTCDtlsTransport to report DTLS and fingerprinting errors. (Firefox bug 1805447).

Changes for add-on developers

• Adds support for the sandbox manifest key, enabling extensions to designate pages that load with an opaque origin, without direct access to extension APIs. A sandboxed page can use eval() and similar constructs that are otherwise blocked by the extension's content security policy. (Firefox bug 1685123)

Experimental web features

These features are shipping in Firefox 154 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config page and set it to true. You can find more such features on the Experimental features page.

• Truncating content with line-clamp: layout.css.line-clamp.enabled

  The line-clamp CSS property now works without the -webkit- vendor prefix, though at this stage it does not support the no-ellipsis and <string> values. (Firefox bug 2042986).

• Percentage values for text-decoration-inset: layout.css.text-decoration-inset-percentage.enabled

  The text-decoration-inset CSS property now supports percentages as values. The percentage value specifies the size of the inset as a percentage of the font-size. (Firefox bug 2044602).

• CSS Typed Object Model Level 1 (Nightly): layout.css.typed-om.enabled

  The CSS Typed Object Model API (as defined in the CSS Typed Object Model Level 1 specification) is now implemented. This simplifies CSS property manipulation by exposing CSS values as typed JavaScript objects rather than strings. (Firefox bug 2051047).