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All fingerprint checksEnvironment & locale

timezone is not UTC

Check id timezone-not-utc

What an ordinary browser yields

A region zone that matches where the connection appears to originate — e.g. 'Europe/Berlin' behind a German exit.

What a detector infers

The check resolves the Intl zone and fails only when it is exactly 'UTC' or 'Etc/UTC'. The mechanism is population statistics, not tampering: virtually every server, container image and CI runner defaults to UTC, while consumer machines are configured to a local region during setup. So a detector reading UTC learns something about the host class — datacenter-shaped rather than desktop-shaped — and will weigh it more heavily when the egress IP resolves to a residential region that is plainly not UTC. Because a genuine user in Iceland or the UK in winter can legitimately be at UTC, the check is 'info' severity and is not scored.

How to resolve it

Set a real-region timezone that matches your proxy exit region (geoip=True, or timezone='Europe/Berlin'). Leave it as-is if your environment genuinely sits at UTC and that agrees with your egress.

What is a timezone / IP mismatch?

Read in the wild by

Kasada

Pulls the long-form zone name out of `new Date().toString()` and tests it for exact equality with 'Coordinated Universal Time' — one arm of a bundle it evaluates only once hardwareConcurrency, platform and language already match a common automation default.

2.txt:32213-32215 — `r6["tn"] = r4; r5 = _5784["tn"]; r4 = r5 === "Coordinated Universal Time";` (literal also in the string table at 2.txt:1). `tn` is produced by `_5672` = func_01df55 (assigned 2.txt:31506, defined 2.txt:32096), which returns `new Date().toString().match(/\((.+)\)/)[1]`. Gated at 2.txt:32188-32199 on `hwc === 16` / `platform === "Win32"` / `language === "en-US"`, with `tn` initialised to null at 2.txt:32184; sibling arm compares `gpv` to the SwiftShader ANGLE renderer string at 2.txt:32221.

Every attribution traces to a published artifact. See the sources and their limits.

Nearby checks in Environment & locale

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Who builds this test

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 Environment & locale 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 Environment & locale — the family timezone-not-utc belongs to.