Inspecting data in about:webrtc during a call can be helpful when diagnosing WebRTC call troubles. Doing so in real time while participating in a call is not always an option. Recent work in about:webrtc has made it easy to get data out of Firefox and into your notes, your bug reports, or your service tickets.

Today, we’ll go over the different information that the about:webrtc page holds and how to get it out into your clipboard quickly and effectively.

What is the about:webrtc page

Most browsers have about: pages that show internal configurations and states. You can navigate to about: pages in the address bar to view and configure browser settings, discover advanced information, and more. In Firefox, you can find a list of all about: pages at about:about.

We’ve made a number of improvements to the about:webrtc page where you can see call signaling, network traffic, and connection establishment and incorporate this data into your notes or bug reports. There are four main sections on this page; RTCPeerConnection Statistics, a Connection Log, User-modified WebRTC configs, and Media Context. We’ll look at these elements in more detail in the following sections below.

In order to analyze the current state of a call a number of stats are exposed to web developers. As a user, getting access to these stats from within a call can be challenging. For that reason, a live view of this data is also available inside of about:webrtc.

Sometimes, less is more. Perhaps you don’t need an entire stats report, but a sub-class of stats would suffice. Many UI sections let you copy data using a rollover copy button. Most sections are derived from stats reports and work like the “Copy Report” button. It will copy the stats objects from the most recently displayed stats report data to the clipboard in JSON format. Adding this to a bug in a Bugzilla follows the same steps as attaching a full stats report. The SDP section, which is not derived from the stats reports, can also be copied as JSON.

Sometimes more is more. about:webrtc stores a rolling window of stats reports which can be copied to the clipboard via the “Copy Report History” button. By default the duration of the history is one minute. This can be useful for inspecting data after the fact from a transient event. The process for adding this data to a Bugzilla bug report is identical to adding a single stats report.

While not new, it is important to note that the “Save Page” button at the bottom of about:webrtc will, when pressed, produce a static HTML file with the contents of about:webrtc. A save dialog will appear, allowing the user to save this file to their machine.

Anywhere a preference appears in about:webrtc one can click the copy button to copy the preference path to the clipboard. That can then be pasted into the search field inside of about:config. Neat.

JSON can be directly attached to a bug in Bugzilla via the “Attach File” button in the “Attachment” section. You can paste the JSON-formatted report into the “File” field, choose “JSON source (application/json)” from the “select from list:” content-type option, and add a brief description in the “Description” field.