Firefox Beta and Developer Edition
Release Notes

Text selected in PDFs is now highlighted clearly like in normal web pages. The selection color also follows OS settings like high-contrast mode.

Video seeking is now significantly faster on macOS, making scrubbing and jumping to a point in a video much more responsive.

In Firefox for Android, Bookmarks Search now shows up to 75 results per query, making it easier to find your bookmarks without refining your search.

The JSON Viewer now shows a breadcrumb path at the bottom for the selected entry.

Firefox now supports Iterator.prototype.includes(), allowing developers to check whether an iterator contains a given value without first converting it to an array.

Added a time picker user interface to <input type="time"> and <input type="datetime-local">, making selecting a time more accessible and intuitive.

Firefox now supports the sibling-index() and sibling-count() CSS functions. These functions allow an element to be styled with calculations that use its index among its siblings and its total count of siblings (including itself), respectively.

Firefox now supports the Iterator.prototype.join method that allows joining an iterator into a string, similar to Array.prototype.join.

Added support for the No-Vary-Search HTTP response header for the HTTP disk cache. Servers can now declare which URL query parameters are irrelevant to the response, allowing Firefox to reuse cached resources across parameter variations and improving cache hit rates.

Firefox now supports new Iterator.prototype.chunks and Iterator.prototype.windows methods that allow consuming an iterator as either overlapping or non-overlapping subsequences of configurable size.

Firefox now supports the text-box-trim and text-box-edge CSS properties, and the associated text-box shorthand. These properties allow you to control the leading space above and below text, enabling simpler and consistent vertical spacing and alignment.