Download Firefox Developer Edition 125.0

New
- Firefox now prompts users in the US and Canada to save their addresses upon submitting an address form, allowing Firefox to autofill stored address information in the future.
- Firefox has expanded its download protection and now more proactively blocks downloads from URLs that are considered to be potentially untrustworthy.
- The URL Paste Suggestion feature provides a convenient way for users to quickly visit URLs copied to the clipboard in the address bar of Firefox. When the clipboard contains a URL and the URL bar is focused, an autocomplete result appears automatically. Activating the clipboard suggestion will navigate the user to the URL with 1 click.
- Firefox now provides an option to enable Web Proxy Auto-Discovery (WPAD) while configured to use system proxy settings.
- Users of tab-specific Container add-ons can now search in the Address Bar for tabs that are open in different containers. Special thanks to volunteer contributor atararx for kicking off the work on this feature!
- It is now possible to highlight in PDFs.
This feature is part of a progressive roll out.
What is a progressive roll out?
Certain new Firefox features are released gradually. This means some users will see the feature before everyone does. This approach helps to get early feedback to catch bugs and improve behavior quickly, meaning more Firefox users overall have a better experience.
- Firefox now supports AV1 codec for Encrypted Media Extensions (EME).
Fixed
- Fix for MFSA 2024-15 is included in Firefox Desktop and DevEdition 125.0b3 builds and newer.
Changed
- In a group of radio buttons where no option is selected, the tab key now only reaches the first option, rather than every option being reachable with tab. The arrow keys navigate between options as they do when there is a selected option. This makes keyboard navigation more efficient and consistent.
- Firefox for Android no longer includes the variant and extension of BCP47 in the Accept-Language header of HTTP requests for better interoperability with other browsers.
Developer

Web Platform
- Added support for the content-box and stroke-box keywords of the transform-box CSS property.
- Support for SVGAElement.text was removed in favor of the more widely-implemented SVGAElement.textContent method.
- The popover global attribute is used to designate an element as a popover element. The element won't render until it becomes shown, it will then render on top of other page content.
- align-content works now in block layout, allowing block direction alignment without needing a flex or grid container.
- Enabled WebAssembly multi-memory by default. Wasm multi-memory allows wasm modules to use and import multiple independent linear memories. This enables more efficient interop between modules, and better polyfills for upcoming wasm standards like the component model.
- Added support for Unicode text segmentation to JavaScript.
- Firefox now supports the navigator.clipboard.readText() web API. A paste context menu will appear for the user to confirm when attempting to read clipboard data not provided by the same-origin page.