Yes, that’s a reasonable request. This is fairly rough and far from complete, but here are the notable changes off the top of my head:
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We enable support for Google Safe Browsing. Mull enabled Safe Browsing as well; but Tavi didn’t have an API key, so it never actually worked on Mull. We added the API key, so it works. Our plan is to disable Safe Browsing by default and leave it up to the user to enable, but on the current build (134.0.0), it’s partially enabled by default due to a bug, but this will be fixed next release.
-
As discussed above, we now use Phoenix instead of Arkenfox. Phoenix includes the hardening of Arkenfox, but is also more comprehensive, and we’re using the
Androidversion, which is specifically tailored to Android.
In terms of how Phoenix itself compares to Mull/Arkenfox, Phoenix:
- Disables Origin Trials
- Disables X-Frame Options Error Reporting
- Covers more telemetry prefs for defense in depth
- Removes special privileges granted to certain Mozilla domains
- Disables Preconnect
- Disables Early Hints
- Upgrades local content as part of HTTPS-Only Mode
- Blocks insecure display content & object subrequests
- Disables DNS over HTTPS connectivity checks
- Fixes IPv6 connectivity issues when using DNS over HTTPS
- Enables Certificate Transparency
- Disables Region updates
- Sets the fallback network geolocation provider to BeaconDB instead of Google
- Enables WebRTC, but enables mDNS host obfuscation and forces it to exclude local IP addresses. This effectively breaks WebRTC; but it’s superior to outright disabling it like Mull did, as disabling it is fingerprintable. This approach still prevents any leaks. This is similar to the behavior of Arkenfox, though even stricter; Disabling WebRTC entirely was a Mull-specific change.
- Prevents using system accent colors due to fingerprinting concerns
- Enables
fdlimfor math, due to it being more resistant to fingerprinting This is already enabled via ‘Resist Fingerprinting’ (RFP), which both Mull & IronFox enable by default, but this still enables it for users who disable RFP. - Explicitly enables various protections from Firefox’s ‘Strict’ tracking protection that are active on desktop, but not mobile in most cases (Ex. bounce tracking protection).
- Uses dFPI/TCP (Firefox’s Total Cookie Protection) instead of FPI for state partitioning, as FPI is no longer maintained and causes more breakage. Arkenfox itself also uses dFPI instead of FPI, so enabling FPI was a Mull-specific change.
- Restricts tracking referers
- Improves Firefox’s built-in query stripping by expanding the list to match Brave & LibreWolf’s
- Disables password truncation
- Disables more JIT
- Disables SharedArrayBuffer using
window.postMessage - Prevents websites from downloading unlimited files without user consent… can be abused for denial of service
- Enables additional Spectre mitigations
- Enables Cookie
Same-Site Schemeful,Lax by default, andNone only if secure - Enables Trusted Types
- Disables marking JIT codepages as both writable and executable
- Enables certain performance enhancements & minor QOL changes
- Disables ETP WebCompat & Heuristics to harden Firefox’s tracking protection
- Etc…
Like @Cue said, I’m planning to create the comparison table as mentioned above, which will give you a better idea of these changes and what they mean in context. I’m also working on overhauling Phoenix’s features page in general, as it’s fairly outdated at this point.
In the meantime, this should give you a rough idea of IronFox/Phoenix’s changes compared to Mull/Arkenfox.
Also worth noting that this is based off of IronFox’s current release. IronFox’s next release will contain more changes when compared to Mull due to various patches we’ve introduced, such as:
- Enabling per-site process isolation (Fission) + the option to disable it
- Enabling Firefox’s built-in cookie banner blocking
- Disabling search suggestions
- Replacing Mozilla’s recommended extensions with exclusively uBlock Origin
- Disabling Password Manager/Autofill by default
- Etc…