I was recently in a situation where, in trying to optimize a site for performance reasons, I needed to track down what was generating some above-the-fold content. Specifically, this was a client's site that we had inherited as part of a Drupal support contract. On mobile-sized screens, the homepage was displaying a banner ad for the company's mobile app, which provided a download link for the app.
With this breakpoint in place, Chrome will pause the page rendering process after any change to the DOM is detected. You can then take control of the process with some basic debug steps, like stepping into, out of, or over each function call, or resuming script execution as normal.
Once you think you've located the function calls you're looking for, you can examine each individual function call by clicking on its name in the call stack, which will bring up the exact code in question within your DevTools console.