Clark-Browser

What's new

This is a stealth refresh of the Clark browser Linux binary for the Chromium 148.0.7778.96 line.

• Makes Notification.permission and the permissions query surface report a prompt/default-compatible state under Clark fingerprint mode, fixing the sannysoft HEADCHR_PERMISSIONS failure.
• Seeds coherent desktop screen metrics, including screen.width, screen.height, avail*, outer*, DPR, and 24-bit color depth.
• Adds a platform-aware WebGL GPU fallback with Chrome-like WebGL version/shading strings and a Chrome-ish extension allowlist.
• Enables Clark runtime noise defaults for client rects, canvas measureText, and canvas image data.
• Hardens the Linux and E2B smoke suites for UA-CH, WebGL, sannysoft, audio, and canvas seed-differential behavior.
• Fixes background Linux build container launch ordering.

Binary

Asset: clark-browser-linux-x64.tar.gz

SHA256:

902934003d3183dc13fd254ef14d9286a8b47396414e9f851801479c3b3fb4a9

Verification

• Local Python syntax checks and import tests passed.
• Patch dry-runs passed against the Chromium source snapshot for notification, screen, and WebGL patches.
• AWS c7i.4xlarge Linux build completed and in-container smoke passed.
• Actual E2B Ubuntu 24.04 sandbox with agent-browser 0.27.0 passed tests/integration_smoke.py --webgl, including UA/UA-CH, WebGL NVIDIA ANGLE fallback, sannysoft HEADCHR checks, notification permissions, audio seed differential, and canvas seed differential.

Live detector sweep (2026-05-20)

Run environment: E2B Ubuntu 24.04 sandbox, agent-browser 0.27.0, released Linux binary downloaded from this GitHub release and SHA256-verified.

| Target | Result | Evidence |
|---|---:|---|
| Baseline JS/CDP probe | PASS | navigator.webdriver=false, plugins.length=5, platform=Win32, coherent 1440x900 screen, WebGL Google Inc. (NVIDIA) / ANGLE (...) Direct3D11; permissions query returned prompt. |
| Cloudflare challenge smoke (nowsecure.nl) | PASS | Loaded target without visible challenge/block text. |
| SannySoft | PASS | WebDriver missing, Chrome present, HEADCHR UA/permissions/plugins/iframe all ok. |
| Antoine Vastel headless test | FAIL | Explicit verdict: You are Chrome headless. |
| BrowserLeaks Client Hints | PASS | Windows + Google Chrome UA-CH, no HeadlessChrome. |
| BrowserLeaks WebGL | PASS | Google/NVIDIA ANGLE, WebGL/WebGL2 enabled, no SwiftShader/llvmpipe text. |
| Incolumitas, Pixelscan, BotD demo, CreepJS | OBSERVED | Loaded and captured; no stable passive verdict for several pages. CreepJS still shows a Headless panel. |

Full table and raw captured JSON are published in the repo:
docs/bot-detection-results.md.

Antoine Vastel follow-up

The original live detector sweep marked Antoine Vastel's headless test as failed. Follow-up investigation isolated this to the HTTP Accept-Language header rather than a JS-only browser surface.

Targeted E2B + agent-browser rerun using the same released binary:

| Launch variant | Antoine result |
|---|---|
| Without --accept-lang | You are Chrome headless |
| With --accept-lang=en-US,en | You are not Chrome headless |

clarkbrowser.get_default_stealth_args() and the smoke tests now include --accept-lang=en-US,en; the public results table has been updated with the follow-up evidence.