In more recent versions of Firebug, the developers pulled out the integrated Firebug trace function. If you want the functionality, you should install the FBTrace Extension; it’s almost required if you want to develop a Firebug Extension. The FBTrace Extension is at https://getfirebug.com/wiki/
I built an extension following the following tutorials and code:
The extension logged out the details of API requests to specific applications and filtered on those requests so I could debug an issue when loading multiple of them on the same page.
A couple tips for developers using the NetListeners are:
The url and parameters are in file.href
The method is file.method
The headers are an array which can be retrieved from file.requestHeaders property. Each object is a name – value pair. header.name / header.value.
The requestBody is really file.postText
The responseBody is best returned using netUtils.js context.sourceCache.loadText(