(Note that this page is a work in progress and may be updated frequently)

Brave for desktop is built on top of the open-source Chromium project. We add features on top of what is already there and we also remove features or pieces of the code. These deviations we make that touch the core Chromium code are done via patching.

Chromium is not the same as Google Chrome. For some differences, see https://chromium.googlesource.com/chromium/src/+/master/docs/chromium_browser_vs_google_chrome.md.

How it works

If you wanted to do an audit of the code, you would start with the brave-browser repository. Our wiki has instructions about what steps need to be done to perform a build after cloning the source

Chromium source is fetched

The gclient utility (part of depot tools) will fetch the official Chromium source code. The tag that is fetched is captured in our package.json(for example,70.0.3538.35). All of the source code will be downloaded into the./src/folder

Brave code is fetched

As part of the setup process, we also fetch our own code. The brave-core repository has the code that makes the browser Brave. The branch that should be checked out is also contained in that package.json. There is also a DEPS file in brave-core that pulls in sub-dependencies (such as the brave-extension)

Hooks are run

After the gclient sync runs and fetches all the code (including brave-core), the hooks are run. One of the hooks that runs applies the patches (which you can see here) that are contained in brave-core. If you'd like to know more details about HOW the patching works, you can view our patching wiki page.

What Chromium features are removed for privacy/security reasons?

Services & Features We Disable Entirely

• Chrome Privacy Sandbox. There are several APIs bundled together in Privacy Sandbox and we aim to disable all given our concerns.
• Google accounts integration ("GAIA") is disabled
• All features that send data to Google are removed from settings
• DNS prefetching is disabled
• Chrome Google URL Tracker is disabled
• Domain service reliability is disabled
• Inline extensions are disabled
• Background sync is disabled
• Hyperlinkpingattribute is disabled
• Disable Battery API
• Disable WebBluetooth API
• WebRTC debug log uploading is disabled
• Uploading settings after resetting profile is disabled
• Retrieving OEM default settings after resetting profile is disabled
• Tracing crash log uploading is disabled
• Google Cloud Messaging is disabled
• Firebase Cloud Messaging is disabled
• Push client channel updates are disabled
• Network time tracker is disabled
• Google-assisted address normalization is disabled
• Specific features are disabled on startup via the CLI (search fordisabled_features)
• Remove dl.google.com repository from Linux packages
• Disable metrics reporting
• Disable Lookalike URLs Navigation Suggestions
• Disable Reporting Observers and Reporting API
• Disable Scroll To Text Fragment
• Disable Motion Sensors
• Disable navigator.credentials
• Disable Android OTP integration
• Disable SXG
• Disable NFC
• Disable WebBundles
• Disable Client Hints (lang)
• Disable Direct / Raw Sockets
• Disable Idle Detection
• Disable Notification Triggers
• Disable File System API
• Disable Digital Goods API
• Disable Serial API
• Disable Federated Learning of Cohorts (FLoC)
• Disable Network Information API
• SCT auditing
• Site affiliation fetcher (part of the password manager)
• Disables kOptimizationGuideFetchingForSRP
• Disable Web Environment Integrity
• Disable Popular Sites (AKA Top Sites)
• Disable Trust Tokens / Private State Tokens

Services We Proxy Through Brave Servers

Google does not receive any information about which client is performing these requests (not even your IP address).

• SafeBrowsing requests are proxied
• Geolocation requests are proxied
• Plugin updates are proxied
• Certificate revocation requests are proxied
• Requests for CRLSets are proxied
• Requests for component updates are proxied
• Requests for spellcheck dictionaries are proxied
• Requests in devtools are proxied
• Requests for Search Engine page favicon (Android) are proxied

Proxied endpoints

• https://dl.google.com/release2/chrome_component/*crl-set*
• https://*.gvt1.com/edgedl/release2/chrome_component/*
• https://*.gvt1.com/edgedl/chrome/dict/*.bdic
• https://storage.googleapis.com/update-delta/hfnkpimlhhgieaddgfemjhofmfblmnib/.+crxd
• https://safebrowsing.googleapis.com/
• https://sb-ssl.google.com/
• https://safebrowsing.google.com
• https://ssl.gstatic.com
• https://gstatic.com
• https://update.googleapis.com
• https://chrome-devtools-frontend.appspot.com
• https://clients2.googleusercontent.com
• https://clients2.google.com
• https://clients4.google.com
• https://chrome-devtools-frontend.appspot.com
• https://accounts.google.com
• https://*.infura.io
• https://*.gvt1.com/edgel/chromewebstore/*/*
• https://*.gvt1.com/edgedl/release2/*/*
• http://dl.google.com/release2/*/*

Modified Features and Functionality

• Cookies:
  • Cookies are given a maximum lifetime of 7 days for cookies set through Javascript and 6 months for cookies set through HTTP
  • Session Cookies are cleaned up on restart if "Continue where you left off" mode is enabled (which is default in Brave).
  • Third-party cookies are always blocked at the HTTP header level, but we give JavaScript access to partitioned ephemeral storage to pages (learn more about partitioned ephemeral storage).
• The Battery API always returns a fixed value.
• Referrer values are capped tostrict-origin-when-cross-originand can only be tightened by referrer policy, not weakened. In addition, cross-origin requests from a.onionservice have an emptyRefererheader and anullOriginheader just like the Tor Browser.
• .onion entries are replaced with "null" in document.location.ancestorOrigins() unless such entries are same-origin with the innermost frame.
• Hangouts extension is disabled by default. We also disable log uploading to Google's servers: https://github.com/brave/brave-browser/issues/1993.
• Media Router (Chromecast) is disabled by default on Desktop. You can turn it on by toggling the switch in brave://settings.
• Download protection remote lookups omit URLs and filenames (https://github.com/brave/brave-core/pull/6763).
• Have StorageManager.estimate report a fixed value( issue #11543)
• Many features have randomness added or values generalized as a defense against fingerprinting, including:
  • Canvas readback methods
  • User Agent, follow ups in issues #12097, #12638, #14740
  • enumerateDevices
  • Web Audio Serialization
  • WebGL Debug
  • Plugins
  • hardwareConcurrency
  • deviceMemory
• The list of hostnames with pinned CA certificates is replaced with a Brave-specific one.
• Restore gesture requirement for async clipboard write access
• Dangerous download warnings are always shown when Safe Browsing is OFF, but a flag to disable the warnings is available for advanced users.
• Functionality from the Chromium side panel has been merged into the Brave Sidebar.
• Web Serial API is OFF but a flag to enable is available for advanced users.
• Enhanced the geolocation permission dialog to inform the user whether the site they are visiting has requested location data with the enableHighAccuracy option.
• Reporting Observers are enabled but don't work (calling will no-op). See here for where it was disabled and see here for where it was re-enabled but made to do nothing.
• Open Search adding engines has a toggle (Index other search engines) and is disabled by default.
• Access to Storage Access API is disabled in Brave by always rejecting the permission request.
• When group policy is in place, Brave does NOT disable secure DNS. Chrome/Chromium will disable secure DNS in the UI and force the administrator to define a policy if they want a value other than Off. See here and here.

Comments

Some of the above (along with other issues) were previously tracked in https://github.com/brave/brave-browser/issues/13.

You may notice some requests to Google domains. Some of these, such asclients*.google.com and update.googleapis.com are needed to check for extension updates if you installed extensions.

How does Brave compare to ungoogled-chromium?

Description of ungoogled-chromium, per their GitHub page:

ungoogled-chromium is Google Chromium, sans integration with Google. It also features some tweaks to enhance privacy, control, and transparency(almost all of which require manual activation or enabling).

We have an issue captured for pulling in relevant patches from theungoogled-chromiumproject. Theungoogled-chromiumproject similarly has an issue captured where they mention pulling in patches from Brave.