[6] DocumentOrShadowRoot インターフェイスは、
Document と ShadowRoot が実装しています >>3。
[4] NoInterfaceObject です >>3。
[1] Shadow: add DocumentOrShadowRoot mixin · whatwg/dom@4183385 ( 版) https://github.com/whatwg/dom/commit/418338575c7f79a18d20ebcc88c19834366379cf
[2] [Fix #91] Use DocumentOrShadowRoot Mixin · w3c/webcomponents@b12afbb ( 版) https://github.com/w3c/webcomponents/commit/b12afbb7b2c22b5033aab70ad569c00af4278cf9
[8] Make Fullscreen work with shadow trees (TakayoshiKochi著, ) https://github.com/whatwg/fullscreen/commit/611a4046b0569752d198093e36edd736851877a6
[9] Use interface mixins in IDL (romandev著, ) https://github.com/whatwg/dom/commit/12b069802b771c145fd3b1917c5b82f2a8c1ff9f
[10] DocumentOrShadowRoot is a mixin (#141) (saschanaz著, ) https://github.com/whatwg/fullscreen/commit/b705140eca265f7ff5de813e1f08cb359a70613f
[11] DocumentOrShadowRoot is a mixin by saschanaz · Pull Request #141 · whatwg/fullscreen () https://github.com/whatwg/fullscreen/pull/141
[12] Define DocumentOrShadowRoot's activeElement (rakina著, ) https://github.com/whatwg/html/commit/5b84d194c5ca0be9b738e0d46078131ca4a5f422
[13] Define DocumentOrShadowRoot.activeElement by rakina · Pull Request #4837 · whatwg/html () https://github.com/whatwg/html/pull/4837