Information on Navigation Timings and how they work can be found at:
https://www.w3.org/TR/navigation-timing/
Navigation timing results are available on the waterfall chart or from the XML feed using Details=BrowserAction.
For example, substituting your own PID and Site ID in the following XML request
https://xmlreporter.dotcom-monitor.com/reporting/xml/responses.aspx?pid=XXXXXXXXXXXXXXXXXXX&Site=XXXXXX&Type=Detail&Options=RequestDetails&Details=BrowserAction
returns values in the following XML format:
<BrowserAction Type="BrowserPerformance"><FetchStart>553</FetchStart><DomainLookupStart>553</DomainLookupStart><DomainLookupEnd>553</DomainLookupEnd><ConnectStart>553</ConnectStart><ConnectEnd>553</ConnectEnd><RequestStart>553</RequestStart><ResponseStart>553</ResponseStart><ResponseEnd>556</ResponseEnd><DomLoading>553</DomLoading><DomInteractive>1094</DomInteractive><DomContentLoadedEventStart>1094</DomContentLoadedEventStart><DomContentLoadedEventEnd>1248</DomContentLoadedEventEnd><DomComplete>2320</DomComplete><LoadEventStart>2339</LoadEventStart><LoadEventEnd>2344</LoadEventEnd></BrowserAction>