[16] 妥当なカスタム要素名は、 次の要件をすべて満たす文字列です >>3。
[22] PCENChar
として使える文字の一覧は、 >>5 にあります。
[85] [Custom] Added defintions for registration, custom element name, and …, dglazkov, , https://github.com/WICG/webcomponents/commit/6826c33554fceaddc2cbf339847e8dbf84bea197
[86] >>85 この時点では x-
から始まるのがカスタム要素名だった。
[84] [Custom]: Refactored all references to what exactly custom element na…, dglazkov, , https://github.com/WICG/webcomponents/commit/8bc87545ec31b8ce30e1ae690c4e3af5faaa031c
[83] [Custom]: Polished custom element name definition., dglazkov, , https://github.com/WICG/webcomponents/commit/6bef6e0f640c3278f7a29bebe17de540918cad35
[82] [Custom]: Updated custom element name definition., dglazkov, , https://github.com/WICG/webcomponents/commit/df4217c34f15ccf7bd8b5e3e716f76375a715648
[81] [Custom]: Added custom element name blacklist., dglazkov, , https://github.com/WICG/webcomponents/commit/fc9f58ed2ea4d4b5fb4bc5d8957d70b9ed0c8d1d
[80] Bug 20973 - [Custom]: Restrict custom elements to NCName., dglazkov, , https://github.com/WICG/webcomponents/commit/dd58e700d3aeecda95702120074749610083313b
[2] Add custom elements to HTML · whatwg/html@6e7eaa4 ( 版) https://github.com/whatwg/html/commit/6e7eaa4bd2912965fd83766f99f984f249531f3a
[6] Editorial: tidy up PCENChar definition (#1202) ( (domenic著, )) https://github.com/whatwg/html/commit/f0f2e2ca836582e30eeec7c10dc3832b12bc8177
NCNameChar
からASCII大文字を除外したものです >>7。