[1] IRC logs: freenode / #whatwg / 20090714 (2009-09-19 17:07:55 +09:00 版) http://krijnhoetmer.nl/irc-logs/whatwg/20090714#l-487

[2] Add framespacing to obsolete-attributes list · whatwg/html@a7e2dd5 (2015-09-02 16:35:42 +09:00 版) https://github.com/whatwg/html/commit/a7e2dd5ba7153541102f417f939acfe1cdd8e5ec