Files
Nikhil bb62213e84 fix: install linux sysroot in configure, not via gclient hook (#653)
* fix: install linux sysroot in configure, not via gclient hook

`gn gen` was failing on the arm64 leg with `Missing sysroot
(//build/linux/debian_bullseye_arm64-sysroot)`. The previous design
relied on `git_setup` writing `target_cpus` to `.gclient` so that
`gclient sync`'s DEPS hook would download the cross-arch sysroot. That
chain breaks for any chromium_src that was synced before cross-arch
support landed (the hook is gated on .gclient state at sync time) and
for partial pipeline runs that skip git_setup entirely. Nothing in
configure declared or verified its sysroot precondition.

Make configure self-healing: on Linux, invoke
`build/linux/sysroot_scripts/install-sysroot.py --arch=<target>`
directly before `gn gen`. install-sysroot.py is idempotent (stamp file
+ SHA check), fast when already installed, and decoupled from .gclient
— it's exactly what the failing assertion's error message recommends.
The script accepts our arch names directly: `x64` translates to `amd64`
internally via ARCH_TRANSLATIONS, and `arm64` is a valid pass-through.

Also temporarily pin release.linux.yaml to x64 only while we validate
the sysroot bootstrap end-to-end. Flip back to `[x64, arm64]` once
arm64 is green.

* chore: pin release.linux.yaml to arm64-only for sysroot bootstrap test

x64 already builds cleanly — the failing leg is arm64 cross-compile from
an x64 host. Pin the config to arm64 to exercise the new
install-sysroot.py path in configure without burning time on x64.
Flip back to [x64, arm64] once arm64 is green.
2026-04-07 11:12:21 -07:00
..
2026-03-04 18:31:20 -08:00

BrowserOS Browser (Chromium Fork)

Custom Chromium build with AI agent integration, enhanced privacy patches, and native MCP support.

Based on Chromium 146.0.7680.31 · Built with Python 3.12+ · Licensed under AGPL-3.0

What This Is

This package contains the BrowserOS browser build system — everything needed to fetch Chromium source, apply BrowserOS patches, and produce signed binaries for macOS, Windows, and Linux. The build system is a Python CLI that orchestrates the entire pipeline from source to distributable.

BrowserOS patches add:

  • Native AI agent sidebar and new tab integration
  • MCP server endpoints baked into the browser
  • Enhanced privacy via ungoogled-chromium patches
  • Custom branding, icons, and entitlements
  • Keychain access group management (macOS)
  • Sparkle auto-update framework (macOS)

Prerequisites

Requirement Details
Disk space ~100 GB for Chromium source + build artifacts
Python 3.12+
macOS Xcode + Command Line Tools
Linux build-essential, clang, lld, and Chromium's Linux deps
Windows Visual Studio 2022, Windows SDK

Directory Structure

packages/browseros/
├── build/                   # Build system (Python CLI)
│   ├── __main__.py          # CLI entry point
│   ├── browseros.py         # Main app definition
│   ├── modules/
│   │   ├── setup/           # Chromium source fetch and setup
│   │   ├── patches/         # Patch application logic
│   │   ├── apply/           # Apply patches to source tree
│   │   ├── extract/         # Extract patches from modified source
│   │   ├── feature/         # Feature flag management
│   │   ├── package/         # Binary packaging
│   │   ├── sign/            # Code signing (macOS, Windows)
│   │   ├── ota/             # Over-the-air update support
│   │   └── resources/       # Resource management
│   ├── config/              # Build configuration
│   └── features.yaml        # Feature flag definitions
│
├── chromium_patches/        # BrowserOS patches applied to Chromium source
│   ├── chrome/browser/      # Browser UI and feature patches
│   ├── components/          # Component patches (e.g., os_crypt)
│   └── ...                  # Organized to mirror Chromium source tree
│
├── chromium_files/          # New files added to Chromium (not patches)
├── series_patches/          # Ordered patch series
├── resources/               # Icons, entitlements, signing resources
│   └── entitlements/        # macOS entitlements (app, helper, GPU, etc.)
│
├── tools/
│   └── bdev                 # Developer tool
│
├── CHROMIUM_VERSION          # Pinned Chromium version (MAJOR.MINOR.BUILD.PATCH)
├── BASE_COMMIT              # Base Chromium commit hash
├── pyproject.toml           # Python project config
└── requirements.txt         # Python dependencies

Build System

The browseros CLI manages the full build lifecycle:

# Install the build system
pip install -e .

# Or use uv
uv pip install -e .

Key commands:

browseros setup          # Fetch and prepare Chromium source
browseros apply          # Apply all patches to Chromium source
browseros build          # Build BrowserOS binary
browseros package        # Package into distributable (DMG, installer, AppImage)
browseros sign           # Code sign the binary (macOS/Windows)

Patch System

BrowserOS applies patches on top of vanilla Chromium. Patches are organized in two directories:

  • chromium_patches/ — Individual file patches, organized to mirror the Chromium source tree. Each file here replaces or modifies the corresponding file in Chromium.
  • series_patches/ — Ordered patch series applied sequentially.

Adding a New Patch

  1. Make your changes in the Chromium source tree
  2. Use browseros extract to pull changes back into patch format
  3. Place the patch in the appropriate directory mirroring Chromium's structure
  4. Test with a full browseros apply && browseros build cycle

Chromium Version Pinning

The exact Chromium version is pinned in CHROMIUM_VERSION:

MAJOR=146
MINOR=0
BUILD=7680
PATCH=31

To update the base Chromium version, update this file and BASE_COMMIT, then resolve any patch conflicts.

Signing (macOS)

macOS builds require code signing for Keychain access, Gatekeeper, and notarization:

  • Entitlements are in resources/entitlements/ (app, helper, GPU, renderer, etc.)
  • Designated requirements pin to Team ID for Keychain persistence across updates
  • The signing module is at build/modules/sign/macos.py

Feature Flags

Feature flags are defined in features.yaml and control which BrowserOS-specific features are compiled into the build. The feature module (build/modules/feature/) manages flag resolution at build time.