[1] 518110 – nuke HTMLBaseFontElement interface ( (2013-01-14 00:07:27 +09:00 版)) <https://bugzilla.mozilla.org/show_bug.cgi?id=518110>

[2] Fix which built-in elements can be customized (domenic著, 2016-11-17 01:31:58 +09:00) <https://github.com/whatwg/html/commit/7d6b279b0d2bc30752700155a043b65441fe12e3>