a second browser target resolves the same timezone as the window
A SharedWorker resolves the same IANA timezone as the window — or the row declines, because SharedWorker is unavailable in some engines and blocked in some embedding and privacy configurations.
What a detector infers
This audit already compares the window's timezone against a dedicated worker. This row asks a sharper version of the question, and the sharpness is the whole point. A SharedWorker is not just another thread — it is a separate browser TARGET. The DevTools command that overrides a timezone applies per target.
So an automation layer that sets the zone the convenient way, on the page it is driving, produces a browser whose page reports the intended zone while every target created afterwards reports the host's real one. A dedicated worker does not reliably catch that; a separate target does, and it costs one message to ask.
The inference for a detector is strong because there is no honest configuration in which one browser resolves two different IANA zones at the same instant: the zone comes from one place, and two readings of one place cannot disagree. What the disagreement identifies is precisely where the setting was applied — above the browser rather than inside it — which is a stronger statement than 'this timezone looks wrong', because it names the mechanism rather than the value.
How to resolve it
Set the timezone at the browser level — a launch flag, or the engine's own configuration — rather than through a per-target automation override. A per-target override reaches the page and misses workers, newly created targets and the browser process, and any one of those can be asked by a page that thinks to.
Read in the wild by
CloakBrowser Pro releases
A stealth browser's release notes record moving timezone and locale out of the per-target automation layer and into browser-level flags, precisely because the automation override left workers, new targets and the browser process on the host values.
CHANGELOG entries moving locale/timezone from the automation context to --fingerprint-timezone / --lang binary flags
CloakHQ/CloakBrowser CHANGELOG.mdEvery attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Navigator identity
- location.origin is the serialisation of its own protocol, host and port
location-origin-coherenceAn origin is not stored next to a URL, it is serialised from it: for an http or https document, origin is exactly the scheme, followed by… - navigator.vendor is the constant the measured engine compiles in
navigator-vendor-vs-enginenavigator.vendor is not a preference or a setting — it is a string constant compiled into the engine. - navigator.oscpu names the same OS family as the user-agent
ua-oscpu-os-family-coherencenavigator.oscpu is a property only Gecko still exposes — Chromium removed it and WebKit never had it — so this check is silent on every… - a worker resolves the same IANA timezone as the main thread
worker-main-timezone-coherenceA browser has one host timezone, and the specification ties both the main-thread global and every worker global to it, so a real browser… - the keyboard layout maps the OEM keys the way one real Windows layout would
keyboard-layout-single-originA keyboard layout is not a set of independent key mappings — it is one artifact the operating system hands over whole. - navigator.appVersion is the user agent minus its leading token
appversion-vs-useragentnavigator.appVersion is not an independent fact. In Blink and WebKit it is computed from the User-Agent at read time — literally the UA with… - Trusted Types hands back the branded object its own type demands
trusted-types-value-invariantTrusted Types is a typed API, not a boolean feature flag, and that is the whole of the check. - the user agent on the wire and the one JavaScript reports describe the same browser
ua-wire-vs-navigatorYour user agent is asserted on two channels built by different layers: the network stack writes the header, and the renderer answers…
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Navigator identity checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Navigator identity — the family timezone-shared-worker-vs-window belongs to.