Well, look at that. I discovered (purely by accident, I was dragging and dropping *I thought* into IE11 but no, it was Edge!) that Windows 10 EDGE browser now supports drag and drop.
I couldn’t find much out there in regards to an announcement (Sneaky, I guess while we the public test it ;). But it’s here in 10.0.10586 (Build 10586). So far so good.