Service Worker was turned on by default in Edge included in Windows 10 Insider Preview Build 17063.Jimmy commented
We’re pleased to announce that the details and summary elements are now under development :)
Push API is enabled by default in Edge included in Windows 10 Insider Preview Build 17063.
The dialog element is now on the backlog with a priority of medium. You can track status changes at https://dev.modern.ie/platform/status/dialogelementformodals/