Big BUG ，I compare Chrome, IE, Edge, Edge dev. only Edge dev can not open a local html file. Not network problem, Beaucse I had turn off network.
the html file is here:
you can download to test it! not a html file, but all html file! you can new a html file to try!
Sorry for the late reply, but this issue should be fixed now as of Edge Dev Version: 18.104.22.168.
Please let me know if you run into any problems with Dev and local HTML files.