Despite this feature having been implemented and working for some (see #6) I'm still not seeing my Javascript sources' URLs being mapped to their local paths in stack traces in my debug console, which look like this:

TypeError: bounds.aspect is not a function
    at Size.resizeToFit (http://localhost:3000/js/Geometry.js:103:31)
    ...

The part of the URL after the protocol is clickable, but results in a file not found error. By the way I'm talking about plain JS files with no sourcemaps. My debug launch config looks like this:

{
    "name": "Launch localhost",
    "type": "chrome",
    "request": "launch",
    "url": "http://localhost:3000",
    "webRoot": "${workspaceRoot}/client"
}

Everything is bang up to date:
Code v1.11.1
Debugger for Chrome extension v2.7.3
Chrome version 57.0.2987.133