What powers kernel.org?

Last seen Aug 2026 · 44 technologies across 20 categories

Caching

Varnish
since Aug 2018

CDN

Amazon S3
since Mar 2023
Cloudflare
since Feb 2024

CRM

Salesforce
since Mar 2023

Documentation

Sphinx
since Mar 2022
Zendesk
since Mar 2023

Font scripts

Font Awesome
since Jan 2023

Issue trackers

Bugzilla v5.1.1
since Feb 2019

JavaScript frameworks

Vue.js
since Feb 2023

JavaScript libraries

core-js v2.5.1
since Sep 2021
jQuery v3.6.0
since Aug 2018
jQuery Migrate v3.0.0
since Jan 2019
jQuery UI v1.11.2
since Aug 2018
lit-element v4.2.2
since Oct 2024
lit-html v3.3.3
since Mar 2023
Moment.js v2.18.1
since Oct 2020
Selectize
since Nov 2022
Underscore.js
since Mar 2022
YUI v2.9.0
since Feb 2019

Miscellaneous

DocuSign
since Mar 2023
HTTP/3
since Aug 2024
Open Graph
since Sep 2022
PWA
since Aug 2022
Pygments
since Mar 2022
RSS
since Dec 2022
Webpack
since Jan 2023

Operating systems

CentOS
since Jan 2022

PaaS

Amazon Web Services
since Mar 2023
GitHub Pages
since Mar 2023

Payment processors

Stripe
since Mar 2023

Performance

Turbo
since Mar 2023

Programming languages

Perl
since Feb 2019
PHP
since Aug 2018

Security

Cloudflare Bot Management
since Feb 2024
HSTS
since Sep 2022

Static site generator

Hugo
since May 2026

UI frameworks

Bootstrap
since Aug 2018
Element UI
since Jul 2023

Web servers

Apache HTTP Server
since Aug 2018
Nginx
since Apr 2018

Webmail

Apple iCloud Mail
since Mar 2023
Google Workspace
since Mar 2023

Wikis

DokuWiki
since Aug 2018
MediaWiki
since Aug 2018

AI Crawlers

Blocks all crawlers by default in robots.txt (User-agent: *). Checked Sep 2026.

Training crawlers

  • AI2Bot Blocked
  • Applebot-Extended Blocked
  • Bytespider Blocked
  • ClaudeBot Blocked
  • cohere-training-data-crawler Blocked
  • Diffbot Blocked
  • FacebookBot Blocked
  • Google-CloudVertexBot Blocked
  • Google-Extended Blocked
  • GoogleOther Blocked
  • GPTBot Blocked
  • ImagesiftBot Blocked
  • img2dataset Blocked
  • meta-externalagent Blocked
  • PanguBot Blocked
  • SBIntuitionsBot Blocked
  • Webzio-Extended Blocked

Search and AI assistants

  • Amazonbot Blocked
  • Applebot Blocked
  • Claude-SearchBot Blocked
  • DuckAssistBot Blocked
  • OAI-SearchBot Blocked
  • PerplexityBot Blocked
  • PetalBot Blocked
  • YouBot Blocked

User-request fetchers

  • ChatGPT-User Blocked
  • Claude-User Blocked
  • GoogleAgent-Mariner Blocked
  • meta-externalfetcher Blocked
  • MistralAI-User Blocked
  • Perplexity-User Blocked

The other 2 AI crawlers we track are not mentioned and are blocked by the catch-all rule (User-agent: *).

  • robots.txt found
  • llms.txt not found
  • ai.txt not found
  • Sep 2026 claude-searchbot added to robots.txt
  • Sep 2026 claude-user added to robots.txt
  • Sep 2026 claude-web added to robots.txt
  • Sep 2026 claudebot added to robots.txt
  • Sep 2026 oai-searchbot added to robots.txt
  • Sep 2026 cohere-ai added to robots.txt

See who blocks each AI crawler across the web

Top search keywords

KeywordPositionEst. monthly visits
linux #6 10,200
vfs file system #2 5,400
virtual file system #3 3,200
linux kernel #2 1,100
numa #6 410
rcu #11 340
git pull #6 220
latest linux kernel #1 180
archive site #60 160
relea #64 160
git checkout #8 120
pagemap #1 120
centos #76 100
gnu #67 100
linux kernel download #1 97
download linux kernel #1 97
yuv #3 86
linux swapping #1 79
kernel-based virtual machine #16 78
ftrace #1 73
ftrace #1 73
sparse #74 70
linux source code #3 70
non uniform memory access #14 68
linux kernel development #2 63

The site's top keywords in Google (US), with the visits each one is estimated to bring per month.

Top backlinks

Top links pointing at the site, one per source domain, strongest first. The anchor text opens the page carrying the link.

AI Crawlers

All crawlers blocked

Full breakdown

Audience

  • 68% desktop
  • 32% phone
  • United States
  • India
  • United Kingdom
  • China
  • Poland
  • Switzerland

Where the site's Chrome visitors come from, largest estimated audience first.

Open Page Rank

8.73 / 10 · ranked #993 of all domains

8,985 referring domains · OpenPageRank

Search traffic

29,000 est. monthly organic visits (US)

6,432 keywords in Google's top 30

Core Web Vitals

LCP0.5 s
INP25 ms
CLS0
TTFB400 ms

Real user p75, Chrome UX Report, Aug 2026.

Page

  • Language: English
  • Weight: 0.1 MB · 15 requests

Homepage as crawled by the HTTP Archive, Aug 2026.

Subdomains

HostTechs
dracut.wiki.kernel.org 20
b4.docs.kernel.org 12
erofs.docs.kernel.org 11
hwmon.wiki.kernel.org 10
iwd.wiki.kernel.org 10
wireless.wiki.kernel.org 10
wireless.docs.kernel.org 9
backports.docs.kernel.org 8
docs.kernel.org 8
korg.docs.kernel.org 8
ata.wiki.kernel.org 7
btrfs.wiki.kernel.org 7
bugzilla.kernel.org 6
social.kernel.org 6
backports.wiki.kernel.org 5
cdn.kernel.org 5
ext4.wiki.kernel.org 5
git.wiki.kernel.org 5
i2c.wiki.kernel.org 5
perf.wiki.kernel.org 5
raid.wiki.kernel.org 5
rt.wiki.kernel.org 5
subspace.kernel.org 5
www.kernel.org 5

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