Please Add a Debug message for loading extensions

Expected Behavior

To give a debug message for custom extension for devolopers like

• This URL is not valid
• This is not a js extension file
• There is problem in line # (I don't know if this is possible)

I am requesting for this because i just recently started block extension devolopment for scratch so i don't know much where it has gone wrong if it not loads properly due to a error or problem.

[SheepTester]

The browser doesn't make much info available when it fails to load. Instead, you should check the browser console. I probably should make it tell you that