Many extensions change the page to do their job: a wallet adds an object, a dark mode adds attributes, a translator adds elements, antivirus web protection adds its own script. Any site can read those marks, and they say a lot about you. Here are the ones this page found.
53 sniffers · no permission asked
You're probably from . You speak , and your computer runs on with a clock.
You're on , using , with a screen and graphics: .
You like , and . . Your fonts drop a hint: . As for your age, .
Referer · document.referrernavigator.languagesIntl.DateTimeFormatIntl …timeZoneIntl …hourCycleIntl.Locale weekInfoIntl.NumberFormatnavigator.keyboardspeechSynthesisprefers-color-schemeprefers-reduced-motioncolor-gamut · dynamic-rangeprefers-contrast · forced-colorsdisplay-modedoNotTrack · GPCnavigator.cookieEnabledpermissions.querypdfViewerEnablednavigator.webdriverbait elementwindow.ethereum · DOM markshistory.lengthcanvas measureTextuserAgentDatauserAgentData.brands…architecture · bitnessscreen · devicePixelRatiorequestAnimationFramescreen.isExtended · screenXinnerWidth · availHeightWebGL RENDERERnavigator.gpu adapter.infoWebGL2 · MAX_TEXTURE_SIZEhardwareConcurrencynavigator.deviceMemorymaxTouchPoints · pointernavigator.getBatterynavigator.connectionWebRTC host candidateenumerateDevicesAudioContext.sampleRatePublicKeyCredentialbluetooth.getAvailabilityMediaSource.isTypeSupportedrequestMediaKeySystemAccessstorage.estimateError.messagecanvas.toDataURLWebGL getParameterOfflineAudioContextfonts → SHA-256SHA-256canvas × 2It can't list them, but it can see what they leave behind: objects like window.ethereum, attributes on the page, elements they insert, scripts they add. Some extensions leave nothing and stay invisible.
Extensions narrow you down: a crypto wallet, developer tools or a particular translator says something about who you are, and adds to your fingerprint.
Extensions that change your user agent, language or time zone, or wrap the drawing functions fingerprints use, rewrite what sites read. That's what the check in front looks for.