[1] Remove <applet> (zcorpan著, ) <https://github.com/whatwg/html/commit/b9b9d60f9451c05f8e8d542e4094f987ae1a5fb8>
[2] Remove <applet> (except for parsing rules) · Issue #454 · whatwg/html () <https://github.com/whatwg/html/issues/454>
[3] Remove <applet> (except for parsing rules) · Issue #454 · whatwg/html () <https://github.com/whatwg/html/issues/454>