GitHub code editor (github.dev) on Microsoft Edge browser says the error request initialize failed with message: Webassembly is not defined
and also missing syntax highlighting while opening a file (e.g. a simple .cs file)
All you need to do to fix that is to go to the edge settings
> privacy, search, and services
> scroll down to reach option Enhance your security on the web
, and just turn it off
(note that you must completely turn it off, not setting it on Balanced or strict.)
after that refresh the github and see it working...
hope this saves you time.