ua-tracer
by Paul Kinlan
trace MtwVENvA
what does a user agent actually fetch, follow & run?
Trace MtwVENvA
First seen: 2026-07-05 22:19:19.218 UTC
User-Agent: Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)
Bot verification: Not a known bot (no IP-range check applies).
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.
| Received | Δ | Kind | Method | User-Agent |
|---|---|---|---|---|
| 2026-07-05 22:19:19.218 UTC | +0 ms | homepage | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (14){
"accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/heif,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"host": "uatracer.com",
"priority": "u=0, i",
"sec-fetch-dest": "document",
"sec-fetch-mode": "navigate",
"sec-fetch-site": "none",
"sec-fetch-user": "?1",
"traceparent": "00-95237601831797d6b380f57fb48b1b8a-9260bb06800116e8-01",
"tracestate": "",
"upgrade-insecure-requests": "1",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:20.906 UTC | +1688 ms | CSS | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (14){
"accept": "text/css,*/*;q=0.1",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "u=0",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "style",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-47700c5e6ef0c63bd621fe71d3c4c81d-9d8ea35e588e5629-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.142 UTC | +1924 ms | preload (image) | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-aa2b016a72bc1f01d182acc8944d4554-4790fa6d9829d8d9-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.380 UTC | +2162 ms | iframe document | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/heif,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "u=0, i",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "iframe",
"sec-fetch-mode": "navigate",
"sec-fetch-site": "same-origin",
"traceparent": "00-d5bfe003b08bd2812f46fcf952dfe5ae-a91cf49e7b4e2896-01",
"tracestate": "",
"upgrade-insecure-requests": "1",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.398 UTC | +2180 ms | JS | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (14){
"accept": "*/*",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "u=1",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "script",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-42d92b78922866271b2b9510dd4f855a-ff321a3651b53ac3-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.401 UTC | +2183 ms | ES module | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "*/*",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"origin": "https://uatracer.com",
"priority": "u=1",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "script",
"sec-fetch-mode": "cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-44ad385b82d867e2581d4685178044bf-e621ad5354a79cc5-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.402 UTC | +2184 ms | image | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-317c57b85e10fa0c2012a7eba79f670d-68c61c2c730a7c38-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:21.618 UTC | +2400 ms | CSS @import (nested stylesheet) | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (14){
"accept": "text/css,*/*;q=0.1",
"accept-encoding": "gzip, deflate, br, zstd",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "u=0",
"referer": "https://uatracer.com/r/MtwVENvA/h6IyC1mM/style.css",
"sec-fetch-dest": "style",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-e917b59200cb9fef4de9bc34fa466fa0-ee499efb23f6123d-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:22.007 UTC | +2789 ms | image inside iframe | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/r/MtwVENvA/h6IyC1mM/iframe",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-28d55a57527c0cb6e79ffd76a310a4bc-b786235c97d55ba9-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:22.944 UTC | +3726 ms | JS executed beacon | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-6d9e6bc7554d8f957f62aee8ab68a1f9-88d1a5cea2e1e5ed-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:23.182 UTC | +3964 ms | CSS background-image | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/r/MtwVENvA/h6IyC1mM/style.css",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-aaa4cdd5e26b70c626f4c7809d879f65-b796b20d9ce4d6ec-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-05 22:19:23.185 UTC | +3967 ms | ES module executed | GET | Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/) |
request headers (15){
"accept": "image/heif,image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
"accept-encoding": "identity",
"accept-language": "zh,zh-CN;q=0.9",
"cookie": "ua-tracer-trace=MtwVENvA",
"host": "uatracer.com",
"priority": "i",
"range": "bytes=0-499",
"referer": "https://uatracer.com/",
"sec-fetch-dest": "image",
"sec-fetch-mode": "no-cors",
"sec-fetch-site": "same-origin",
"traceparent": "00-0cc3771d4cd75583b9dbce6d906964f8-e1db4ab8b00c2126-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (Linux; Android 5.0) AppleWebKit/537.36 (KHTML, like Gecko) Mobile Safari/537.36 (compatible; Bytespider; https://zhanzhang.toutiao.com/)",
"via": "HTTP/2 ord.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-07 22:39:57.725 UTC | +174038507 ms | image | GET | Mozilla/5.0 (compatible; crawler) |
request headers (9){
"accept": "*/*",
"accept-encoding": "gzip, deflate",
"accept-language": "en-US",
"connection": "keep-alive",
"host": "uatracer.com",
"traceparent": "00-91f80e24eddbdeccdd5efe1edb36e71c-a8b96ce21f9a7917-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (compatible; crawler)",
"via": "HTTP/1.1 ams.vultr.prod.deno-cluster.net"
}
|
||||
| 2026-07-08 00:41:16.397 UTC | +181317179 ms | image inside iframe | GET | Mozilla/5.0 (compatible; crawler) |
request headers (9){
"accept": "*/*",
"accept-encoding": "gzip, deflate",
"accept-language": "en-US",
"connection": "keep-alive",
"host": "uatracer.com",
"traceparent": "00-61c11f4d46ea7aa8dd0d27b1bcdb4942-be02cdd80c0c9df2-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (compatible; crawler)",
"via": "HTTP/1.1 ord.vultr.prod.deno-cluster.net"
}
|
||||
Client-side resource waterfall
JS executed (beacon hit) but no resource-timing payload was posted (UA may block sendBeacon/fetch or strip the body).