Close all Firefox instances. Delete the dev-edition-default folder inside %APPDATA%\Mozilla\Firefox\Profiles\ (Windows) or ~/Library/Application Support/Firefox/Profiles/ (macOS). Restart Developer Edition—it recreates a clean profile.
: Sends more telemetry data to Mozilla by default to help improve features. Free Access : Full suite of professional tools at no cost.
A: Every 4 weeks, synchronized with Firefox Beta releases. Firefox Developer Edition 134 Free Download
: It is a testing platform and can be less stable than the final release.
Mozilla has already committed to version 135 (scheduled for August 2026). According to the official roadmap, upcoming features include: Close all Firefox instances
Firefox Developer Edition 134, released on January 7, 2025, is a specialized version of the Firefox browser designed specifically for web developers and designers. It serves as a testing ground for the latest web features and experimental tools before they reach the stable release.
You might be thinking, “Can’t I just use standard Firefox?” : Sends more telemetry data to Mozilla by
After downloading the tarball or installer, verify the SHA-256 checksum against the values on Mozilla’s official site to ensure integrity.