Anti-tracking and privacy protections

Firefox ships extensive Enhanced Tracking Protection (ETP) which combines URL classification, cookie partitioning, fingerprinting resistance, and content blocking.

Pieces

• URL Classifier (netwerk/url-classifier/) — Safe Browsing-style table-based URL filtering. Tables include mozilla-tracking, analytics, social, cryptomining, fingerprinting, plus Google Safe Browsing's malware/phishing tables.
• Cookie partitioning — Total Cookie Protection: cookies are partitioned per top-level origin so cross-site tracking cookies become useless. Implemented in netwerk/cookie/.
• Fingerprinting resistance — privacy.resistFingerprinting and the more nuanced "Fingerprinting Protection" toggle. See toolkit/components/resistfingerprinting/.
• Content Blocking UI — the shield icon and per-site protections panel in browser/base/content/protections.js and browser/components/protections/.
• Anti-tracking module (toolkit/components/antitracking/) — coordinates all of the above, exposes prefs and probes, applies storage-access exemptions.

Storage Access API

Sites that need cross-site storage access (e.g., embedded SSO) request it via document.requestStorageAccess(), which prompts the user and grants a time-limited exemption. Implementation in dom/storage/ and toolkit/components/antitracking/.

Levels

• Standard (default) — block known trackers + cross-site cookies.
• Strict — also blocks more tracker categories and applies fingerprinting protection.
• Custom — user-defined.

Related

• Networking
• Security