the Web Animations surface is identical in a fresh realm
The same API surface and the same computed timing values in both realms.
What a detector infers
The Web Animations API exposes a small, precisely specified surface: whether Element.animate exists, whether the timeline and KeyframeEffect constructors are present, and what a created animation reports for its playback rate and computed effect duration. The check drives a real animation in each realm and reads those values back, then requires them to agree.
The reason this is worth asking at all is that animation timing is one of the surfaces automation tooling perturbs — either by disabling animations to make pages settle faster, or by driving the clock to skip waits — and doing that in the page world leaves a fresh realm reporting the honest values. Severity is warn rather than critical because the surface is small and a page-level library can legitimately wrap Element.animate.
How to resolve it
If the two realms disagree, something is intervening in animation timing in the page world. Nothing here needs fixing on an ordinary browser.
Read in the wild by
Kasada
Reads the Web Animations surface across seven probes, including a live animation's computed timing.
animation_end_time, animation_playback_rate, animation_duration, animation_progress, animation_play_state, animation_active_duration, animation_overall_progress
Kasada ips.js teardown — the full 427-probe listEvery attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Capability surfaces
- device-level media features are identical in a fresh realm
media-surface-vs-realmMedia features are answered by the layout engine rather than by the JavaScript properties that describe the same machine, which is what… - the codec matrix is identical in a fresh realm
codec-surface-vs-realmcanPlayType answers come from the media stack compiled into the browser, and the shape of that matrix is genuinely informative: branded… - supported <input> types are identical in a fresh realm
input-surface-vs-realmAssigning an unrecognised type to an <input> element does not throw — the element silently falls back to reporting type "text". - emoji advance widths are identical in a fresh realm
emoji-surface-vs-realmEmoji do not render from the page's fonts but from a platform font supplied by the operating system — Segoe UI Emoji on Windows, Apple Color… - the platform theme resolves the CSS system colours coherently
system-colors-vs-platformThe CSS system-colour keywords — Highlight, HighlightText, Canvas, CanvasText, ButtonFace, ButtonText, GrayText and their newer siblings… - the user-agent stylesheet resolves identically in a fresh realm
default-style-values-vs-realmEvery browser ships a user-agent stylesheet: the rules that make a heading bold and a button look like a button before any site CSS exists. - the permission descriptors this build accepts are the platform's, not a lookup table's
permission-name-support-setThe Permissions specification deliberately fixes no list of names. - form-factor-gated APIs match the form factor the client hints claim
platform-gated-apis-vs-form-factorSome Web APIs are not compiled for every platform, so their presence is a fact about the binary rather than about the user agent.
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 Capability surfaces 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 Capability surfaces — the family animation-surface-vs-realm belongs to.