[1] HTML5 Revision Tracker (2010-03-23 22:21:24 +09:00 版) http://html5.org/tools/web-apps-tracker?from=4859&to=4860

[2] HTML5 Revision Tracker (2010-03-23 22:24:54 +09:00 版) http://html5.org/tools/web-apps-tracker?from=4860&to=4861

[3] Official Google Webmaster Central Blog: Google does not use the keywords meta tag in web ranking ( (2011-12-17 11:28:33 +09:00 版)) http://googlewebmastercentral.blogspot.com/2009/09/google-does-not-use-keywords-meta-tag.html

[4] Official Google Webmaster Central Blog: Google does not use the keywords meta tag in web ranking ( (2014-09-02 14:12:10 +09:00 版)) http://googlewebmastercentral.blogspot.jp/2009/09/google-does-not-use-keywords-meta-tag.html

[327] Tamil and Sanskrit Slokas, Venkatesh K. Elayavalli, 2025-07-13T05:58:59.000Z, 1999-11-11T18:08:34.829Z https://web.archive.org/web/19991111180747/http://www.srivaishnava.org/slokas/slokas.htm

 <keywords>Slokas Tamil, Sanskrit, Sri Vaishnavava Slokas, Ramanuja</keywords>
   <link hxburned rel="fontdef" src="http://www.srivaishnava.org/adhawin.pfr">

[5]

RFC 7992 - HTML Format for RFCs (2016-12-17 02:51:45 +09:00) https://tools.ietf.org/html/rfc7992#section-9.28

Each <keyword> element renders its text into the <meta> keywords in
the document's header, separated by commas.
<meta name="keywords" content="html,css,rfc">