The Modern moniker for such apps is Universal Windows Platform, UWP for short. They started out as Metro apps - some said because they used a lot of bandwidth
In it's early incarnations Edge needed a shim ==>>
https://github.com/MicrosoftEdge/edge-launcher. I used it with calibre's Open With until MS killed off Edge's ePUB reader feature
Interestingly the current incarnation of Edge does appear in the calibre's offer list for PDF's, and the offer list for (x)html files in the editor.
BR