uBlock Origin Lite Now Available for Safari on macOS and iOS via TestFlight

The popular content-blocking extension uBlock Origin Lite (uBOL) is now available for Safari users on both macOS and iOS through Apple's TestFlight program, marking a significant expansion of this privacy tool's availability.

Safari Support Brings Content Blocking to Apple Ecosystem

After considerable development effort to overcome Safari-specific technical hurdles, uBlock Origin Lite can now be tested by Safari users. The TestFlight beta version addresses several compatibility issues that previously prevented the extension from functioning properly in Apple's browser. This development is particularly noteworthy as it brings improved content blocking capabilities to iOS users, who have historically had limited options for comprehensive ad and tracker blocking.

I currently use Wipr on macOS and iOS. I'll give this a spin, however, what are the biggest downsides of the MV3 variant over the original MV2?

uBlock Origin Lite for Safari - Key Details

• Availability: TestFlight beta for both macOS and iOS
• Installation: Via TestFlight link: https://testflight.apple.com/join/pQTcTyhv
• Requirements: Safari 15.4+
• Key MV3 Limitations:
  • Limited filtering capabilities compared to MV2
  • Filter lists only update with extension updates
  • Minimal user customization options
  • Cannot easily add filters by selecting page elements

Known Technical Issues:

• Problems with excludeMatches in content scripts
• Limitations with shouldLoadOnlyFromOrigins parameter
• Web-accessible resources not working properly
• Zapper functionality issues

MV3 Limitations Affect Functionality

As users in the discussion point out, uBlock Origin Lite operates under Manifest V3 (MV3) restrictions, which come with significant limitations compared to the full MV2 version. The most notable drawbacks include reduced filtering capabilities and the fact that filter lists only update when the extension itself is updated, rather than independently. Additionally, user customization is severely limited—users cannot easily tweak filters on a per-site basis or add new filters by selecting page elements directly. These limitations stem from the constraints of the MV3 extension framework that major browsers are moving toward.

Technical Challenges in Safari Implementation

The development team faced several Safari-specific issues during implementation, including problems with the excludeMatches functionality in content scripts, limitations with the shouldLoadOnlyFromOrigins parameter, and difficulties with web-accessible resources. These technical hurdles required workarounds and coordination with Safari's development team, with some issues still being addressed through the WebKit bug tracking system. The TestFlight release represents progress despite these ongoing challenges.

Safari Security Considerations

The discussion also touched on Safari's security model, with some users questioning its security practices compared to other browsers. While there were concerns about site isolation, more recent versions of Safari do implement process isolation for tabs and various browser functions. However, some users referenced the SLAP exploit from earlier this year, which reportedly affected Safari due to deficient site isolation implementation. This highlights the complex balance between adopting new content blocking tools and considering the overall security posture of the browser platform.

For Safari users interested in trying uBlock Origin Lite, the TestFlight link is available in the original issue thread, offering an opportunity to experience improved content blocking while development continues to address the remaining technical limitations.

Reference: Safari issues to resolve for a minimally working uBOL #327