User-Agent

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.3) Gecko/20100101 Firefox/137.3

first seen 2026-08-17 22:34 · last seen 2026-08-18 15:27 · JSON

Distinct clients per day (last 30 days, peak 3/day)

Distinct clients are counted by IP-hash per complete UTC day — unlike observation counts this is insensitive to one chatty client, but NAT merges clients and address rotation splits them.

Decomposed attributes

Browser / clientFirefox 137.3
Operating systemWindows 10.0
Device classdesktop
Noteinferred from the self-declared string — a claim, not a measurement; compare with the wire fingerprints above

Co-observed signals

Signals from other families seen in the same observation. A fingerprint spread thinly across many lower-layer signatures is a classic inconsistency signal.

TLS ClientHello (JA4)

fingerprintco-occurrences
t13d1717h2_5b57614c22b0_3cbfd9057e0d Match?Exact match in Thumbprint's published controlled catalog captures: firefox 148.0.2, firefox 144.0.2, firefox 142.0.1, +6 more.The fingerprint page shows the full measured match list. More on the catalog.2
t13d1513h2_8daaf6152771_748f4c70de1c1
t13d1716h2_5b57614c22b0_eeeea6562960 Match?Exact match in Thumbprint's published controlled catalog captures: firefox 132.0, firefox 134.0.The fingerprint page shows the full measured match list. More on the catalog.1

HTTP request (JA4H)

fingerprintco-occurrences
ge20nn11enus_3901d4197baf_000000000000_000000000000 Match?Exact match in Thumbprint's published controlled catalog captures: firefox 154.0, firefox 152.0.5, firefox 153.0.1, +3 more.The fingerprint page shows the full measured match list. More on the catalog.3
ge20nn12enus_a72b71f519fc_000000000000_0000000000001

HTTP/2 frames (Akamai)

fingerprintco-occurrences
1:65536;2:0;4:131072;5:16384|12517377|1:0:0:42|m,p,a,s2
1:65536;2:0;4:131072;5:16384|12517377|1:0:0:256|m,p,a,s2

TCP SYN (p0f)

fingerprintco-occurrences
4:52+12:0:8960:mss*7,7:mss,sok,ts,nop,ws:df,id+:01
4:54+10:0:1460:32768,10:mss,nop,ws,sok,ts::01
4:50+14:0:1460:65535,9:mss,sok,ts,nop,ws:df,id+:01
4:47+17:0:1460:mss*44,10:mss,sok,ts,nop,ws:df,id+:01

TCP SYN (JA4T)

fingerprintco-occurrences
62720_2-4-8-1-3_8960_71
32768_2-1-3-4-8_1460_101
65535_2-4-8-1-3_1460_91
64240_2-4-8-1-3_1460_101

Country

fingerprintco-occurrences
DE · Germany2
NL · Netherlands1
FR · France1

Network (ASN)

fingerprintco-occurrences
AS60729 · Stiftung Erneuerbare Freiheit1
AS215125 · Church of Cyberology1
AS205100 · F3 Netze e.V.1
AS213873 · OUIDO Hosting1