ungoogled-chromium Documentation

1. Project Overview & Quickstart (ungoogled-software/ungoogled-chromium) Copy Chapter

File: README.md Copy Chapter

ungoogled-chromium

A lightweight approach to removing Google web service dependency

Help is welcome! See the docs/contributing.md document for more information.

Objectives Copy Chapter

In descending order of significance (i.e. most important objective first):

1. ungoogled-chromium is Google Chromium, sans dependency on Google web services.
2. ungoogled-chromium retains the default Chromium experience as closely as possible. Unlike other Chromium forks that have their own visions of a web browser, ungoogled-chromium is essentially a drop-in replacement for Chromium.
3. ungoogled-chromium features tweaks to enhance privacy, control, and transparency. However, almost all of these features must be manually activated or enabled. For more details, see Feature Overview.

In scenarios where the objectives conflict, the objective of higher significance should take precedence.

Content Overview Copy Chapter

• Objectives
• Motivation and Philosophy
• Feature Overview
• Downloads
• Source Code
• FAQ
• Building Instructions
• Design Documentation
• Contributing, Reporting, Contacting
• Credits
• Related Projects
• License

Motivation and Philosophy Copy Chapter

Without signing in to a Google Account, Chromium does pretty well in terms of security and privacy. However, Chromium still has some dependency on Google web services and binaries. In addition, Google designed Chromium to be easy and intuitive for users, which means they compromise on transparency and control of internal operations.

ungoogled-chromium addresses these issues in the following ways:

1. Remove all remaining background requests to any web services while building and running the browser
2. Remove all code specific to Google web services
3. Remove all uses of pre-made binaries from the source code, and replace them with user-provided alternatives when possible.
4. Disable features that inhibit control and transparency, and add or modify features that promote them (these changes will almost always require manual activation or enabling).

These features are implemented as configuration flags, patches, and custom scripts. For more details, consult the Design Documentation.

Feature Overview Copy Chapter

This section overviews the features of ungoogled-chromium. For more detailed information, it is best to consult the source code.

Contents of this section:

• Key Features
• Enhancing Features
• Borrowed Features
• Supported Platforms and Distributions

Key Features Copy Section

These are the core features introduced by ungoogled-chromium.

• Disable functionality specific to Google domains (e.g. Google Host Detector, Google URL Tracker, Google Cloud Messaging, Google Hotwording, etc.)
  • This includes disabling Safe Browsing. Consult the FAQ for the rationale.
• Block internal requests to Google at runtime. This feature is a fail-safe measure for the above, in case Google changes or introduces new components that our patches do not disable. This feature is implemented by replacing many Google web domains in the source code with non-existent alternatives ending in qjz9zk (known as domain substitution; see docs/design.md for details), then modifying Chromium to block its own requests with such domains. In other words, no connections are attempted to the qjz9zk domain.
• Strip binaries from the source code (known as binary pruning; see docs/design.md for details)

Enhancing Features Copy Section

These are the non-essential features introduced by ungoogled-chromium.

• Add many new command-line switches and chrome://flags entries to configure new features (which are disabled by default). See docs/flags.md for the exhaustive list.
• Add Suggestions URL text field in the search engine editor (chrome://settings/searchEngines) for customizing search engine suggestions.
• Add more URL schemes allowed to save page schemes.
• Add Omnibox search provider "No Search" to allow disabling of searching
• Add a custom cross-platform build configuration and packaging wrapper for Chromium. It currently supports many Linux distributions, macOS, and Windows. (See docs/design.md for details on the system.)
• Force all pop-ups into tabs
• Disable automatic formatting of URLs in Omnibox (e.g. stripping http://, hiding certain parameters)
• Disable intranet redirect detector (extraneous DNS requests)
  • This breaks captive portal detection, but captive portals still work.
• (Iridium Browser feature change) Prevent URLs with the trk: scheme from connecting to the Internet
  • Also prevents any URLs with the top-level domain qjz9zk (as used in domain substitution) from attempting a connection.
• (Windows-specific) Do not set the Zone Identifier on downloaded files

Borrowed Features Copy Section

In addition to the features introduced by ungoogled-chromium, ungoogled-chromium selectively borrows many features from the following projects (in approximate order of significance):

• Inox patchset
• Bromite
• Debian
• Iridium Browser

Supported Platforms and Distributions Copy Section

See docs/platforms.md for a list of supported platforms.

Other platforms are discussed and tracked in this repository's Issue Tracker. Learn more about using the Issue Tracker under the section Contributing, Reporting, Contacting.

Downloads Copy Chapter

Automated or maintained builds Copy Section

ungoogled-chromium is available in the following software repositories:

• Arch: Available in the AUR, see instructions in ungoogled-chromium-archlinux
• Debian: Available in OBS, find your distribution specific instructions in the Installing section
• Ubuntu: Available in the XtraDeb PPA as ungoogled-chromium.
• Fedora: Available in COPR as wojnilowicz/ungoogled-chromium. Also available in RPM Fusion as chromium-browser-privacy (outdated).
• Gentoo: Available in ::pf4public overlay as ungoogled-chromium and ungoogled-chromium-bin ebuilds
• OpenMandriva includes ungoogled-chromium as its main browser. The chromium package includes all ungoogling patches.
• macOS: Available in Homebrew as ungoogled-chromium. Just run brew install --cask ungoogled-chromium. Chromium will appear in your /Applications directory.
• FreeBSD: Available in pkg as www/ungoogled-chromium.
• OpenBSD: Available in ports as www/ungoogled-chromium.
• openSUSE: Available as ungoogled-chromium.

If your GNU/Linux distribution is not listed, there are distro-independent builds available via the following package managers:

• Flatpak: Available in the Flathub repo as io.github.ungoogled_software.ungoogled_chromium
• GNU Guix: Available as ungoogled-chromium
• NixOS/nixpkgs: Available as ungoogled-chromium

Third-party binaries Copy Section

If your operating system is not listed above, you can also try to Download binaries from here

NOTE: These binaries are provided by anyone who are willing to build and submit them. Because these binaries are not necessarily reproducible, authenticity cannot be guaranteed; In other words, there is always a non-zero probability that these binaries may have been tampered with. In the unlikely event that this has happened to you, please report it in a new issue.

These binaries are known as contributor binaries.

Source Code Copy Chapter

This repository only contains the common code for all platforms; it does not contain all the configuration and scripts necessary to build ungoogled-chromium. Most users will want to use platform-specific repos, where all the remaining configuration and scripts are provided for specific platforms:

Find the repo for a specific platform here.

If you wish to include ungoogled-chromium code in your own build process, consider using the tags in this repo. These tags follow the format {chromium_version}-{revision} where

• chromium_version is the version of Chromium used in x.x.x.x format, and
• revision is a number indicating the version of ungoogled-chromium for the corresponding Chromium version.

Additionally, most platform-specific repos extend their tag scheme upon this one.

Building the source code: See docs/building.md

Mirrors Copy Section

List of mirrors:

• Codeberg: main repo and ungoogled-software

FAQ Copy Chapter

See the frequently-asked questions (FAQ) on the Wiki

Building Instructions Copy Chapter

See docs/building.md

Design Documentation Copy Chapter

See docs/design.md

Contributing, Reporting, Contacting Copy Chapter

• For reporting and contacting, see SUPPORT.md
• If you're willing to help, check out the Issue Tracker and especially issues, which need help
• For contributing (e.g. how to help, submitting changes, criteria for new features), see docs/contributing.md
• If you have some small contributions that don't fit our criteria, consider adding them to ungoogled-software/contrib or our Wiki instead.

Credits Copy Chapter

• The Chromium Project
• Inox patchset
• Debian
• Bromite
• Iridium Browser
• The users for testing and debugging, contributing code, providing feedback, or simply using ungoogled-chromium in some capacity.

Related Projects Copy Chapter

List of known projects that fork or use changes from ungoogled-chromium:

• Bromite (Borrows some patches. Features builds for Android)
• ppc64le fork (Fork with changes to build for ppc64le CPUs)

License Copy Chapter

BSD-3-clause. See LICENSE

File: devutils/third_party/README.md Copy Chapter

This directory contains third-party libraries used by devutils.

Contents:

• python-unidiff
  • For parsing and modifying unified diffs.

File: devutils/README.md Copy Chapter

Developer utilities for ungoogled-chromium

This is a collection of scripts written for developing on ungoogled-chromium. See the descriptions at the top of each script for more information.

File: docs/building.md Copy Chapter

Building ungoogled-chromium

The recommended way to build ungoogled-chromium is by consulting the repository for your supported platform (links here).

• Linux users: If your distribution is not listed, you will need to use Portable Linux.

If you want to add ungoogled-chromium to your existing Chromium build process, see the next section. Additionally, you may reference the repositories for supported platforms for inspiration.

Integrating ungoogled-chromium into your Chromium build process Copy Chapter

Typically, ungoogled-chromium is built from code in platform-specific repositories. However, ungoogled-chromium can also be included in part or in whole into any custom Chromium build. In this section, we will assume you already have a process to make your own Chromium builds.

NOTE: You may need additional patches and/or build configuration for your supported platform because this repository does not contain all the code necessary for all platforms.

Before continuing, you may find it helpful to have a look through the design documentation.

The following procedure outline the essential steps to build Chromium will all of ungoogled-chromium's features. They are not sufficient to build ungoogled-chromium on their own.

1. Ensure Chromium is downloaded, such as by depot_tools. In most of our supported platforms, we instead use a custom tool to do this.

mkdir -p build/download_cache
./utils/downloads.py retrieve -c build/download_cache -i downloads.ini
./utils/downloads.py unpack -c build/download_cache -i downloads.ini -- build/src

2. Prune binaries

./utils/prune_binaries.py build/src pruning.list

3. Apply patches

./utils/patches.py apply build/src patches

4. Substitute domains

./utils/domain_substitution.py apply -r domain_regex.list -f domain_substitution.list -c build/domsubcache.tar.gz build/src

5. Build GN. If you are using depot_tools to checkout Chromium or you already have a GN binary, you should skip this step.

mkdir -p build/src/out/Default
cd build/src
./tools/gn/bootstrap/bootstrap.py --skip-generate-buildfiles -j4 -o out/Default/

6. Invoke the build:

mkdir -p build/src/out/Default
# NOTE: flags.gn contains only a subset of what is needed to run the build.
cp flags.gn build/src/out/Default/args.gn
cd build/src
# If you have additional GN flags to add, make sure to add them now.
./out/Default/gn gen out/Default --fail-on-unused-args
ninja -C out/Default chrome chromedriver chrome_sandbox

Building FAQ Copy Chapter

My build keeps crashing because I run out of RAM! How can I fix it? Copy Section

Here are several ways to address this, in decreasing order of preference:

1. Decrease the number of parallel threads to Ninja (the -j flag)
2. Add swap space

File: docs/contributing.md Copy Chapter

Contributing

This document contains our criteria and guidelines for contributing to ungoogled-chromium.

If you have small contributions that don't fit our criteria, consider adding them to ungoogled-software/contrib or our Wiki instead.

If you are a developer of an officially-supported platform, be sure to check out the Platform Repository Standards and Guidelines.

List of contents:

• How to help
• Submitting changes
• Criteria for new features

How to help Copy Section

Generally, ungoogled-chromium needs contributors to help:

• Keep up-to-date with the latest stable Chromium, and any problematic changes in the new version that needs modification.
• Help with issues marked with the help wanted tag (usually either questions for other users, or request for help from other developers)
• Review Pull Requests from other contributors
• Implement feature requests ("enhancements" in the Issue Tracker), large or small.
• Implement issues marked with the backlog tag (that are closed).
  • If it requires new code, please read through the Submitting changes section below.

In addition, anyone is free to help others in need of support in the Issue Tracker.

If there are fixes, tweaks, or additions you want to make, continue onto the following section.

Submitting changes Copy Section

Please submit all changes via Pull Requests.

Guidelines:

• You are welcome to submit minor changes, such as bug fixes, documentation fixes, and tweaks.
• If your change has an associated issue, please let others know that you are working on it.
• If you want to submit a new feature, please read through the Criteria for new features below.
• When in doubt about the acceptance of a change, you are welcome to ask via an issue first.

Criteria for new features Copy Section

1. New features should not detract from the default Chromium experience, unless it falls under the project's main objectives (i.e. removing Google integration and enhancing privacy).

   • For larger features, please propose them via an issue first.

2. New features should live behind a setting that is off by default.

   • Settings are usually added via a command-line flag and chrome://flags entries. See the relevant section in docs/developing.md for more information.
   • Unless there are significant benefits, adding the setting to chrome://settings is not recommended due to the additional maintenance required (caused by the infrastructure that backs preferences).

NOTE: In the event that the codebase changes significantly for a non-essential patch (i.e. a patch that does not contribute to the main objectives of ungoogled-chromium), it will be removed until someone updates it.

File: docs/default_settings.md Copy Chapter

Default Settings

Vanilla Chromium settings are not often changed by ungoogled-chromium, however there are some exceptions.
Below is a list of the documented changes to the default Chromium settings.

File: docs/design.md Copy Chapter

Design

This document contains a high-level technical description of ungoogled-chromium and its components.

Overview Copy Chapter

ungoogled-chromium consists of the following major components:

• Configuration
  • Configuration files
  • Source file processors
  • Patches
• Packaging

The following sections describe each component.

Configuration Copy Chapter

Configuration is a broad term that refers to patches, build flags, and metadata about Chromium source code. It consists of the following components:

• Configuration files
• Source file processors
• Patches

The following sections describe each component in more depth.

Configuration Files Copy Section

Configuration files (or config files) are files that store build configuration and source code changes for a build.

IMPORTANT: For consistency, all config files must be encoded in UTF-8.

List of configuration files:

• chromium_version.txt - The Chromium version used by ungoogled-chromium
• revision.txt - The revision of the changes on top of the given Chromium version.
• pruning.list - See the Source File Processors section
• domain_regex.list - See the Source File Processors section
• domain_substitution.list - See the Source File Processors section
• downloads.ini - Archives to download and unpack into the buildspace tree. This includes code not bundled in the Chromium source code archive that is specific to a non-Linux platform. On platforms such as macOS, this also includes a pre-built LLVM toolchain for convenience (which can be removed and built from source if desired).
• flags.gn - GN arguments to set before building.

Source File Processors Copy Section

Source file processors are utilities that directly manipulate the Chromium source tree before building. Currently, there are two such utilities: binary pruning, and domain substitution.

Binary Pruning: Strips binaries from the source code. This includes pre-built executables, shared libraries, and other forms of machine code. Most are substituted with system or user-provided equivalents, or are built from source; those binaries that cannot be removed do not contain machine code.

The list of files to remove are determined by the config file pruning.list. This config file is generated by devutils/update_lists.py.

Domain Substitution: Replaces Google and several other web domain names in the Chromium source code with non-existent alternatives ending in qjz9zk. These changes are mainly used as a backup measure to detect potentially unpatched requests to Google. Note that domain substitution is a crude process, and may not be easily undone.

With a few patches from ungoogled-chromium, any requests with these domain names sent via net::URLRequest in the Chromium code are blocked and notify the user via a info bar.

Similar to binary pruning, the list of files to modify are listed in domain_substitution.list; it is also updated with devutils/update_lists.py.

The regular expressions to use are listed in domain_regex.list; the search and replacement expressions are delimited with a pound (#) symbol. The restrictions for the entries are as follows:

• All replacement expressions must end in the TLD qjz9zk.
• The search and replacement expressions must have a one-to-one correspondence: no two search expressions can match the same string, and no two replacement expressions can result in the same string.

Patches Copy Section

All of ungoogled-chromium's patches for the Chromium source code are located in patches/. This directory conforms to the default GNU Quilt format. That is:

• All patches must reside inside patches/
• There is a patches/series text file that defines the order to apply all the patches. These patches are listed as a relative path from the patches directory.
  • Lines starting with the pound symbol (#) are ignored
  • For lines with patch paths: If there is a space followed by a pound symbol, the text after the patch path will be ignored.

All patch files in ungoogled-chromium must satisfy these formatting requirements:

• Patch filenames must end with the extension .patch
• The content must be in unified format.
• All paths in the hunk headers must begin after the first slash (which corresponds to the argument -p1 for GNU patch).
• All patches must apply cleanly (i.e. no fuzz).
• It is recommended that hunk paths have the a/ and b/ prefixes, and a context of 3 (like the git default).
• All patches must be encoded in UTF-8 (i.e. same encoding as config files).

Patches are categorized into two directories directly under patches/:

1. core: Changes regarding background requests, code specific to Google web services, or code using pre-made binaries. They must be kept up-to-date with all of the changes in Chromium.
2. extra: Changes to features regarding control and transparency. They are not guaranteed to persist across updates to Chromium.

Within each category, patches are grouped by the following:

• debian/ - Patches from Debian's Chromium
  • Patches are not modified unless they conflict with Inox's patches
  • These patches are not Debian-specific. For those, see the debian/patches directory
• inox-patchset/ - Contains a modified subset of patches from Inox patchset.
  • Some patches such as those that change branding are omitted
  • Patches are not modified unless they do not apply cleanly onto the version of Chromium being built
  • Patches are from inox-patchset's GitHub
  • Inox patchset's license
• bromite/ - Patches from Bromite
• iridium-browser/ - Contains a modified subset of patches from Iridium Browser.
  • Some patches such as those that change branding or URLs to point to Iridium's own servers are omitted
  • Patches are not modified unless they conflict with Debian's or Inox's patches
  • Patches are from the patchview branch of Iridium's Git repository. Git webview of the patchview branch
• opensuse/ - Patches from openSUSE's Chromium
• ubuntu/ - Patches from Ubuntu's Chromium
• ungoogled-chromium/ - Patches by ungoogled-chromium developers

Packaging Copy Chapter

Packaging is the process of downloading, building, and producing a distributable package of ungoogled-chromium.

Packaging files use the code from this repository to build ungoogled-chromium. Each platform and configuration has an associated packaging repository under the ungoogled-software organization. For more information about each packaging repository, see the building documentation.

Packaging generally consists of the major steps:

1. Download and unpack the source tree
2. Prune binaries
3. Apply patches
4. Substitute domains
5. Build GN via tools/gn/bootstrap/bootstrap.py
6. Run gn gen with the GN flags
7. Build Chromium via ninja
8. Create package(s) of build output (usually in out/Default)

File: docs/developing.md Copy Chapter

Development notes and procedures

This document contains an assortment of information for those who want to develop ungoogled-chromium.

Information targeted towards developers and other users live in the Wiki.

Contents:

• Branches
• Adding command-line flags and chrome://flags options
• Workflow of updating to a new Chromium version

Branches Copy Chapter

Development is focused on master, and any changes in there should not break anything unless platforms break during a Chromium version rebase.

Larger feature changes or hotfixes must be done in a separate branch. Once they are ready, then a Pull Request can be made onto master (for contributors with write access, merging directly via a git client is fine). After the branch is merged, it should be removed.

Adding command-line flags and `chrome://flags` options Copy Chapter

See docs/how_to_add_your_feature_flag.md in the Chromium source tree for the steps needed. Note that updating tools/metrics/histograms/enums.xml is not required.

For new flags, first add a constant to third_party/ungoogled/ungoogled_switches.cc (by modifying patch resources/patches/ungoogled-chromium/add-third-party-ungoogled.patch). Then, use this constant in the steps outlined above.

Workflow of updating to a new Chromium version Copy Chapter

Tested on Debian 12 (bookworm). Exact instructions should work on any other Linux or macOS system with the proper dependencies.

To gain a deeper understanding of this updating process, have a read through docs/design.md.

Dependencies Copy Section

• quilt
  • This is available in most (if not all) Linux distributions, and also Homebrew on macOS.
  • This utility facilitates most of the updating process, so it is important to learn how to use this. The manpage for quilt (as of early 2017) lacks an example of a workflow. There are multiple guides online, but this guide from Debian and the referenced guide on that page are the ones referenced in developing the current workflow.
• Python 3.10 or newer
  • httplib2 and six are also required if you wish to utilize a source clone instead of the source tarball. pysocks is required for versions of httplib2 v0.30.0 or later.

Downloading the source code Copy Section

Source tarball download (recommended):

mkdir -p build/download_cache
./utils/downloads.py retrieve -i downloads.ini -c build/download_cache
./utils/downloads.py unpack -i downloads.ini -c build/download_cache build/src

Source clone:

./utils/clone.py -o build/src

Updating lists Copy Section

The utility devutils/update_lists.py automates this process. By default, it will update the files in the local repo. Pass in -h or --help for available options.

./devutils/update_lists.py -t build/src

The resulting source tree in build/src will not have binaries pruned or domains substituted.

Updating patches Copy Section

IMPORTANT: Make sure domain substitution has not been applied before updating patches.

1. Run source devutils/set_quilt_vars.sh (or source devutils/set_quilt_vars.fish if you are using the fish shell)
   • This will setup quilt to modify patches directly in patches/
2. Go into the source tree: cd build/src
3. Use quilt to refresh all patches: quilt push -a --refresh
   • If an error occurs, go to the next step. Otherwise, skip to Step 5.
4. Use quilt to fix the broken patch:
   1. Run quilt push -f
   2. Edit the broken files as necessary by adding (quilt edit ... or quilt add ...) or removing (quilt remove ...) files as necessary
      • When removing large chunks of code, remove each line instead of using language features to hide or remove the code. This makes the patches less susceptible to breakages when using quilt's refresh command (e.g. quilt refresh updates the line numbers based on the patch context, so it's possible for new but desirable code in the middle of the block comment to be excluded.). It also helps with readability when someone wants to see the changes made based on the patch alone.
   3. Refresh the patch: quilt refresh
   4. Go back to Step 3.
5. Run quilt pop -a
6. Go back to ungoogled-chromium repo: cd ../..
7. Run devutils/validate_config.py. If any warnings are printed, address them; otherwise, continue to Step 8.
8. Run devutils/validate_patches.py -l build/src. If errors occur, go back to Step 3.

This should leave unstaged changes in the git repository to be reviewed, added, and committed.

Steps for fixing patches after a failed build attempt Copy Section

If domain substitution is not applied, then the steps from the previous section will work for revising patches.

If domain substitution is applied, then the steps for the initial update will not apply since that would create patches which depend on domain substitution. Here is a method of dealing with this:

1. Revert domain substitution: ./utils/domain_substitution.py revert -c CACHE_PATH_HERE build/src
2. Follow the patch updating section above
3. Reapply domain substitution: ./utils/domain_substitution.py apply -r domain_regex.list -f domain_substitution.list -c CACHE_PATH_HERE build/src
4. Reattempt build. Repeat steps as necessary.

Next steps Copy Section

• Submit a Pull Request of these changes to the ungoogled-chromium repo.
• Once the PR is merged, update the repositories of each platform repository that you are maintaining under the ungoogled-software organization.

File: docs/flags.md Copy Chapter

List of flags and switches

This is an exhaustive list of command-line switches and flags introduced by ungoogled-chromium.
Each switch has a corresponding entry on the chrome://flags page which can be filtered by searching for ungoogled-chromium.

If a switch requires a value, you must specify it with an = sign; e.g. flag --foo with value bar should be written as --foo=bar.

NOTE: If you add a command-line argument that is also in chrome://flags, the flag's state will not be indicated in chrome://flags. There is no universal way to ensure command-line flags are taking effect, but you can find if they're being seen by checking chrome://version.

• Available on all platforms Copy Section

  Switch                                          	Description
  --disable-beforeunload	Disables JavaScript dialog boxes triggered by beforeunload
  --disable-grease-tls	Disables GREASE for TLS. Combined with --http-accept-header allows browser to look more like a tor-browser. See https://github.com/ungoogled-software/ungoogled-chromium/issues/783 for more details.
  --disable-search-engine-collection	Disable automatic search engine scraping from webpages.
  --extension-mime-request-handling	Change how extension MIME types (CRX and user scripts) are handled. Acceptable values are download-as-regular-file or always-prompt-for-install. Leave unset to use normal behavior.
  --fingerprinting-canvas-image-data-noise	(Added flag to Bromite feature) Implements fingerprinting deception for Canvas image data retrieved via JS APIs. In the data, at most 10 pixels are slightly modified.
  --fingerprinting-canvas-measuretext-noise	(Added flag to Bromite feature) Scale the output values of Canvas::measureText() with a randomly selected factor in the range -0.0003% to 0.0003%, which are recomputed on every document initialization.
  --fingerprinting-client-rects-noise	(Added flag to Bromite feature) Implements fingerprinting deception of JS APIs getClientRects() and getBoundingClientRect() by scaling their output values with a random factor in the range -0.0003% to 0.0003%, which are recomputed for every document instantiation.
  --force-punycode-hostnames	Convert all Internationalized Domain Names to punycode (ASCII representation of Unicode). See https://github.com/ungoogled-software/ungoogled-chromium/issues/370 for more details.
  --hide-crashed-bubble	Hides the bubble box with the message "Restore Pages? Chromium didn't shut down correctly." that shows on startup after the browser did not exit cleanly.
  --http-accept-header	Changes the default value of the Accept HTTP header sent with HTTP requests. Combined with --disable-grease-tls allows browser to look more like a tor-browser. See https://github.com/ungoogled-software/ungoogled-chromium/issues/783 for more details.
  --keep-old-history	Disables deletion of local browser history after 90 days
  --max-connections-per-host	(from Bromite) Configure the maximum allowed connections per host. Valid values are 6 and 15
  --omnibox-autocomplete-filtering	Restrict omnibox autocomplete results to a combination of search suggestions (if enabled), bookmarks, and internal chrome pages. Accepts search, search-bookmarks, search-chrome, and search-bookmarks-chrome.
  --popups-to-tabs	Makes popups open in new tabs.
  --disabling-javascript-optimization-disables-jit	Disables JIT too if the "JavaScript optimization" setting is turned off

• Available only on desktop Copy Section

  Switch                      	Description
  --bookmark-bar-ntp	Sets the visibility of the bookmark bar on the New Tab Page. Only takes the value never.
  --close-confirmation	Show a warning prompt when closing the browser window. Accepts last (prompt when closing the last window with several tabs) and multiple (prompt only if more than one window is open).
  --close-window-with-last-tab	Determines whether a window should close once the last tab is closed. Only takes the value never.
  --custom-ntp	Allows setting a custom URL for the new tab page. Value can be internal (e.g. about:blank or chrome://new-tab-page), external (e.g. example.com), or local (e.g. file:///tmp/startpage.html). This applies for incognito windows as well when not set to a chrome:// internal page.
  --enable-incognito-themes	Allows themes to change the appearance of Incognito windows.
  --hide-extensions-menu	Hides the extensions container. This includes the puzzle piece icon as well as any pinned extensions.
  --hide-fullscreen-exit-ui	Hides the "X" that appears when the mouse cursor is moved towards the top of the window in fullscreen mode. Additionally, this hides the "Press F11 to exit full screen" popup.
  --hide-tab-close-buttons	Hides the close buttons on tabs.
  --remove-grab-handle	Removes the reserved empty space in the tabstrip for moving the window.
  --scroll-tabs	Determines if scrolling will cause a switch to a neighboring tab if the cursor hovers over the tabs, or the empty space beside the tabs. The flag requires one the values: always, never, incognito-and-guest. When omitted, the default is to use platform-specific behavior, which is currently enabled only on desktop Linux.
  --show-avatar-button	Sets visibility of the avatar button. The flag requires one of the values: always, incognito-and-guest (only show Incognito or Guest modes), or never.
  --tab-hover-cards	Allows removing the tab hover cards or using a tooltip as a replacement. This can be set with the values none or tooltip.

  • Available only on Windows

    Switch              	Description
    --disable-encryption	Disable encryption of cookies, passwords, and settings which uses a generated machine-specific encryption key. This is used to enable portable user data directories.
    --disable-machine-id	Disables use of a generated machine-specific ID to lock the user data directory to that machine. This is used to enable portable user data directories.

Feature flags Copy Chapter

Feature flags are similar to switches with the difference being that they are passed as values for the --enable-features switch. Multiple features can be passed at the same time by separating them with a comma, e.g. --enable-features=flag1,flag2,flag3.
These are also available on the chrome://flags page.

• Available on all platforms Copy Section

  Feature	Description
  MinimalReferrers	Removes all cross-origin referrers and strips same-origin referrers down to the origin. Has lower precedence than NoCrossOriginReferrers.
  NoCrossOriginReferrers	Removes all cross-origin referrers. Has lower precedence than NoReferrers.
  NoReferrers	Removes all referrers.
  ReducedSystemInfo	Reduces the amount of system information obatainable through headers and javascript, also causes hardwareConcurrency to respond with two cores.
  RemoveClientHints	Removes client hints (information sent to servers about your system, similar to a user agent).
  SetIpv6ProbeFalse	Forces the result of the browser's IPv6 probing (i.e. IPv6 connectivity test) to be unsuccessful. This causes IPv4 addresses to be prioritized over IPv6 addresses. Without this flag, the probing result is set to be successful, which causes IPv6 to be used over IPv4 when possible.
  SpoofWebGLInfo	Return generic values for WebGLDebugRendererInfo to remove a potential data leak while preventing potential website breakage.
  IncreaseIncognitoStorageQuota	Makes Incognito and Guest profiles compute the storage quota with the same algorithm that regular profiles use. This makes it harder for websites to detect Incognito mode, but may allow sites to induce heavy memory pressure.

• Available only on desktop Copy Section

  Feature	Description
  ClearDataOnExit	Clears all browsing data on exit.
  DisableLinkDrag	Prevents dragging of links and selected text. Allows selecting text from a middle of a link. Also allows starting selection without first clearing the existing one. This behaviour is similar to the one from older Opera. See https://github.com/ungoogled-software/ungoogled-chromium/pull/2080 and https://github.com/ungoogled-software/ungoogled-chromium/discussions/2055 for more information.
  DisableQRGenerator	Disables the QR generator for sharing page links.

Flags for existing switches Copy Chapter

Chromium contains switches that do no have corresponding entries in chrome://flags. For convenience, ungoogled-chromium has created entries for some of the commonly-used switches.

• Available on all platforms Copy Section

  Switch                      	Description
  --disable-top-sites	Disables the top sites and most visited entries on the new tab page.
  --disable-webgl	Disable all versions of WebGL.
  --enable-low-end-device-mode	Force low-end device mode when set.
  --force-dark-mode	Forces dark mode in UI for platforms that support it.
  --no-default-browser-check	Disables the default browser check.
  --no-pings	Don't send hyperlink auditing pings.
  --webrtc-ip-handling-policy	Restrict which IP addresses and interfaces WebRTC uses.

• Available only on desktop Copy Section

  Switch                      	Description
  --incognito	Start in Incognito.
  --start-maximized	Starts the browser maximized, regardless of any previous settings.

File: docs/platforms.md Copy Chapter

Supported Platforms

This page lists platforms officially supported by ungoogled-chromium, and their associated repositories.

• Android: ungoogled-chromium-android
• Arch Linux: ungoogled-chromium-archlinux
• Debian, Ubuntu, and derivatives: ungoogled-chromium-debian
• Fedora and CentOS: ungoogled-chromium-fedora
• Portable Linux (for any Linux distro): ungoogled-chromium-portablelinux
• Windows: ungoogled-chromium-windows
• macOS: ungoogled-chromium-macos

2. Official Technical Reference & Guides (ungoogled-software/ungoogled-software.github.io) Copy Chapter

Website for ungoogled-chromium

This is a basic website for ungoogled-chromium, based upon Hydra by CloudCannon.

Develop Copy Chapter

This website was built with Jekyll version 3. but should support newer versions as well.

Install the dependencies with Bundler:

$ bundle install

Run jekyll commands through Bundler to ensure you're using the right versions:

$ bundle exec jekyll serve

Changes made while jekyll serve runs will cause Jekyll to regenerate the site automatically (while auto-regeneration is enabled, which is the default)

Posts Copy Section

• Add, update or remove a post in the Posts collection.
• The Staff Author field links to members in the Staff collection.
• Documentation pages are organised in the navigation by category, with URLs based on the path inside the _docs folder.
• Change the defaults when new posts are created in _posts/_defaults.md.

Staff Copy Section

• Reused around the site to save multiple editing locations.
• Add excluded_in_search: true to any documentation page's front matter to exclude that page in the search results.

Navigation Copy Section

• Exposed as a data file to give clients better access.
• Set in the Data / Navigation section.

Footer Copy Section

• Exposed as a data file to give clients better access.
• Set in the Data / Footer section.