ua-tracer by Paul Kinlan

ua-tracer

what does a user agent actually fetch, follow & run?

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Trace kGl3P19n

First seen: 2026-06-23 10:45:01.702 UTC
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0

What this user agent did

Directly-referenced assets:

✗ fetched CSS ✗ fetched JS ✗ fetched image ✗ fetched font (HTML)

Document-level link hints:

✗ fetched favicon ✗ fetched apple-touch-icon ✗ fetched web manifest ✗ fetched preload ✗ fetched prefetch

Second-level follows (proves it parsed the linking file):

✗ followed CSS background-image ✗ followed CSS @font-face ✗ followed manifest icon ✗ followed CSS @import

Frames (does it descend into iframes?):

✗ fetched iframe document ✗ descended into iframe (loaded inner image)

Reporting (a report-only CSP is violated by inline styles; reports can arrive via HTTP headers with no JS, or via in-page beacons):

✗ sent a CSP/Reporting report (any path) ✗ delivered via report-uri/Report-To header (no JS) ✗ delivered via in-page beacon (securitypolicyviolation / ReportingObserver)

Social embed (Open Graph / Twitter card images):

✗ fetched og:image ✗ fetched twitter:image

JavaScript execution:

✗ EXECUTED classic JS ✗ EXECUTED ES module ✗ posted client timing

Server-side request waterfall

Every request the server received for this trace, in receive order. +ms is the delta from the homepage request.

ReceivedΔKindMethodUser-Agent
2026-06-23 10:45:01.702 UTC +0 ms homepage GET Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0
request headers (11) 
{
  "accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
  "accept-encoding": "gzip, deflate, br",
  "accept-language": "en-US,en;q=0.9",
  "host": "uatracer.com",
  "traceparent": "00-f53327c991c7108823b8702b3b436a45-dcc6b1d85c804ee2-01",
  "tracestate": "",
  "upgrade-insecure-requests": "1",
  "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0",
  "via": "HTTP/1.1 ord.vultr.prod.deno-cluster.net",
  "x-deno-userspace-traceparent": "00-f53327c991c7108823b8702b3b436a45-43f46a375a1844c7-01",
  "x-deno-userspace-tracestate": ""
}