Everything your browser hands to every website you visit, the same data anti-fraud tools (SEON, Castle, FingerprintJS) use to recognize you. Open it in two browsers and compare.
Summary collecting…
Browser fingerprint
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Hash of all stable values below. Same value after a restart or in a private window = trackable.
Device fingerprint (cross-browser)
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Screen, CPU, GPU, time zone and fonts only. Same in two browsers = the two can be linked.
FingerprintJS visitorId (what S.O./S.N. store)
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Same open-source library S.O. uses. Same ID in two browsers or after a restart = linked.
IP address
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Click "Copy report" in the other browser, paste it here.