What Mozilla Firefox does
Mozilla Firefox is an open-source browser for Windows, macOS, and Linux built with Mozilla's Gecko engine and SpiderMonkey JavaScript engine. This record retains older en-US Windows x64, macOS, and Linux x86_64 packages for Firefox 154.0.1 in Mozilla's release archive. Mozilla's current-version metadata reports 155.0.1 on September 11, 2026. The separate Windows 32-bit link is a rolling endpoint and resolved to 155.0.1 during that check; it is not the same pinned build. Compare the current supported release before a new deployment. The recorded SHA-256 values come from Mozilla's release manifest; this audit did not independently validate the manifest's OpenPGP signature or run the packages.
Enhanced Tracking Protection uses Mozilla-maintained lists and different Standard, Strict, and Custom settings. It can reduce selected tracking techniques but does not block every tracker, fingerprinting method, malicious page, or data disclosure, and stricter modes can affect site behavior. Add-ons have their own permissions and update channels. Multi-Account Containers is an optional Mozilla extension, not a guarantee that accounts are isolated from operating-system, network, or endpoint observers.
Firefox Sync requires a Mozilla account and connectivity. Mozilla documents client-side encryption for synchronized data, but that protection does not secure an unlocked or compromised endpoint and does not make all browsing traffic private from sites or networks. The package can be staged offline; Sync, updates, add-ons, Safe Browsing data, and normal web use still require network access.