This page attempts to load various resources that are blocked by CSP, or cause other client-side errors. These errors will be reported via the reporting endpoints API using the targets defined in the CSP report-uri directive, Report-To and Reporting-Endpoints headers.
Open your dev console to see the errors, and inspect report submissions in the Chrome developer console in Application -> Reporting API tab.
You should expect to see reports for CSP violations, CSP hashes, Network Error Logging (though this depends on you having visited this page earlier too), and permissions policy violations. There may be reports of other types too.