Use the console, but update all the tokens so they are referring to the browser tokens. Not great as you have to change some of the code.
Activate my profile and then see what value I get after the profile is run. You can view this with the mboxTrace debugging tool (with the authorization token). Here is a help page which outlines how to get the authorization token and how to use the mboxTrace.
Note that for at.js implementations mboxTrace will be part of the mbox request response. If you view the network request in Chrome's debugger wit the preview mode you can easily see the different parts of the trace. For profile scripts you'll find them under profile > after execution > profileAttributes.