The 1st and 3rd Party Activity widget allows you to see the amount of time each Service, Domain and File spent loading on your site, and you can get this information broken out by 1st or 3rd Party content. This widget is available for both Real User and Synthetic Data.
Note: 1st Party content is defined by the "First Party Domains" list in the site settings. All else is marked as 3rd Party.
By default, you'll see a bar graph depicting the load time for All Services, containing the Slowest Services loading Before 120 seconds. You can change each of these options. Click the tabs at the top to switch between the Service, Domain or File view. Likewise, click the 1st Party, 3rd Party or All options to filter the information in the graph below.
The Slowest Services Before selector allows you to filter the results below by the content starting to load before a performance milestone: Onload, Time to Interactive, First Meaningful Paint, First Contentful Paint, Time to DOM Content Loaded, Time to DOM Interactive or 120 seconds.
All of this information is made up of data within the Dashboard Time Period.