the rare typefaces deployed collectors probe for are reported beside the claimed OS
Contextual only. The resolving subset is shown next to the claimed OS rather than judged against a table of what each OS ought to have.
What a detector infers
Font enumeration in a deployed collector is not a sweep of everything installed — it is a short list of deliberately rare faces, chosen because their presence or absence splits the population cleanly. The same short list keeps reappearing across collectors, and these four are read straight out of one commercial agent's font collector: Vrinda, which ships with Windows, and TRAJAN PRO, Univers CE 55 Medium and ZWAdobeF, which arrive with Adobe software.
Knowing the exact list matters more than it looks: a profile that populates a plausible-looking font set but misses the four faces anyone actually probes for has spent its effort in the wrong place. The row is REPORTED and never scored, for the rule this audit applies to every lookup table — the mapping from a face to an operating system drifts. Adobe faces appear on any OS someone installed Creative Suite on, and a Windows install without them is entirely ordinary.
Scoring it would generate false positives against real browsers, so the set is shown beside the claimed OS and the reader draws the conclusion.
How to resolve it
If a persona describes a machine, make sure the fonts it would actually have are the ones present — starting with the faces collectors actually probe for rather than with the size of the list.
Nearby checks in Engine & OS oracles
- Math.tanh rounds the way the claimed OS's libm rounds
math-tanh-os-vs-uaIEEE 754 fixes how a double is stored but does not require transcendental functions to be correctly rounded, so every operating system's C… - which OS hyphenation engine the browser hyphenates through
hyphenation-engine-osWhen CSS asks a browser to hyphenate a long word, the break points come from a dictionary supplied by the operating system — and the… - the CPU architecture matches the architecture the browser claims
cpu-arch-nan-vs-uachIEEE-754 fixes the exponent and the quiet bit of a NaN but leaves the sign bit to the hardware, and the hardware disagrees: an x86 FPU… - JavaScript and WebAssembly read the same CPU
cpu-arch-nan-wasm-vs-jsIEEE-754 leaves the sign bit and payload of a quiet NaN to the implementation, and the two dominant architectures chose differently: x86… - the three heap numbers describe a possible heap
jsheap-triplet-orderingThis check replaces a retired one, and the swap is the lesson. - the platform's system font belongs to the operating system claimed
system-font-vs-claimed-osThe CSS2 system-font keywords — caption, icon, menu, message-box, small-caption and status-bar — are resolved by the HOST platform's font… - typefaces the claimed OS ships as separate faces measure as separate faces
claimed-os-typefaces-are-distinctA font request is answered by the host's font stack, not by the browser and not by anything the user agent sets, so changing… - the number of font families the page can detect is reported for comparison
font-family-count-vs-claimed-osThe two font rows beside this one ask whether the font layer CONTRADICTS the operating system being claimed.
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 Engine & OS oracles 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 Engine & OS oracles — the family rare-face-probe-set-vs-os belongs to.