Firefox Beta

September 3, 2019

Version 70.0beta, first offered to Beta channel users on September 3, 2019


  • The baseline interpreter for JavaScript bytecode execution is now enabled

  • The developer tools accessibility panel now includes an audit for keyboard accessibility

  • The developer tools accessibility panel now includes a color deficiency simulator for systems with WebRender enabled

  • When focused on a toolbar button, users can now type the first (or first few) characters of another button's name to jump directly to that button.

  • Inactive CSS: The Inspector now grays out CSS declarations that don’t affect the selected element and shows a tooltip explaining why.


  • macOS: Vastly reduced power consumption with a more efficient compositor


  • Built-in Firefox pages now follow the system dark mode preference

  • WebRender enabled by default for Windows desktops with Integrated Intel graphics for Low Resolution devices

  • Aliased theme properties have been removed, which may affect some themes

  • The Firefox Accounts toolbar menu has been updated and reorganized to give faster access to account features and services.


  • Developer Information
  • Write snippets of code and iterate on them faster in the WebConsole with the
    new multi-line editor mode. The Enter key adds new lines like in a regular editor. Evaluate with Ctrl + Enter (Cmd + Enter on OSX).

  • Firefox now supports the CSS properties "text-decoration-thickness" and "text-underline-offset", which let web developers control the position and size of text decoration lines.
    Firefox now supports the CSS property "text-decoration-skip-ink", which (by default) makes underlines and overlines skip over any text that they intersect, to improve readability.

  • DOM Breakpoints in Developer Tools allows diagnose with code in a page changes a specific DOM node, including the node's children

All Firefox Beta downloads