[1] Portals () https://rawgit.com/KenjiBaheux/portals/master/index.html
[2] portals/explainer.md at master · KenjiBaheux/portals () https://github.com/KenjiBaheux/portals/blob/master/explainer.md
[3] Issues · KenjiBaheux/portals () https://github.com/KenjiBaheux/portals/issues
[4] Portals spec · Issue #143 · w3c/strategy () https://github.com/w3c/strategy/issues/143
[5] portals/explainer.md at master · WICG/portals () https://github.com/WICG/portals/blob/master/explainer.md
[6] 865565 - chromium - Monorail () https://bugs.chromium.org/p/chromium/issues/detail?id=865565