Launcher-side fixes found by comparing camoufox against stock Firefox 152.0.4
on Linux, Windows 11 and macOS hosts:
- DNT / GPC: BrowserForge draws doNotTrack "1" on most Firefox samples, but a
stock Firefox 152 reports "unspecified" and globalPrivacyControl false; the
stock defaults are used unless the caller sets them, and both are applied as
prefs so the API, the worker and the DNT / Sec-GPC headers agree (#760).
- Timezone and geolocation: the timezone is passed to the browser, and a
configured position sets permissions.default.geo so permissions.query agrees
with the auto-grant (#769, #773).
- hardwareConcurrency: the reported count is the fingerprint's and the browser
is pinned to that many cores (cpu_affinity.py, Linux/Windows), so worker
timing agrees with it; otherwise the host count snapped into the core counts
real machines ship with (never 2, Firefox's resistFingerprinting value).
- Fonts: the OS base is always present in full, OS-version variants are drawn
all-or-nothing, co-shipped groups stay together, Cascadia is never claimed
off Windows, a native macOS/Windows identity claims only the real OS base,
and gfx.font_rendering.fallback.async is off on Linux so per-character
fallback does not depend on cmap-load timing.
- Speech voices: a per-OS installed-voice model (voice-manifests.json) with
the voiceURI formats each backend really produces (voice-uris.json); no
default voice where stock has none.
- WebGL: extensions a release Firefox never exposes are filtered, but
OVR_multiview2 stays for Windows D3D11 renderers, which expose it.
- Media devices: a seeded draw of common per-OS devices with OS-style labels.
- Windows scrollbars follow the drawn Windows version (overlay on 11).
- Glyph-advance perturbation (fonts:spacing_seed) defaults to off: it moved
every measureText width off the value the same font gives on a real machine.
- Launcher prefs are also exported as CAMOU_PREFS_1..N so camoufox.cfg applies
them at startup, and the browser UI locale follows the spoofed locale.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Jake WriterandClaude Opus 5
Cloudymap1e