External Debugger and Copy Debug URL?

I cannot find any documentation of the Designer Tools features for External Debugger and Copy Debug URL. Can someone show me where I would find an explanation of what these are and how to use them?

ig_extdebug

External debugger attempts to open (in the default web browser) a Chromium remote debugging session attached to the web browser that’s “embedded” in the designer. If your OS’s default browser isn’t Chromium based (ie, Firefox, Safari, etc) then this won’t work properly - so you can also Copy Debug Url and manually open a Chromium browser.

Once you do, you’ll get a window with the same dev tools you get in a “real” web browser (the ones you get via Ctrl Shift I/F12), which allows you to open a console, view page source, manually tweak CSS, etc. It’s generally only useful for our development use, but could occasionally be useful for designers, so we left the capability there.

When I select Copy Debug URL and then open Chrome, when I try to paste the URL nothing is there. It does not appear that the copy function works.

Hi ,
My default browser is chrome. when I try to open the external debugger I get the error that the connection was closed . I tried to copy the
image
I tried to use “Copy Debug URL” and pasted it in the chrome but got the same issue .