XHGui is a web application providing a graphical interface for PHP profiling data. It is currently configured to store and display profiling data submitted by request that have a X-Wikimedia-Debug header.
To enable the debug profiler for a request and submit its data to XHGui for inspection, see X-Wikimedia-Debug#Request profiling.
Anyone can use this service to view profiling data. Configuring XHGui (function watches, custom views, etc.) requires WMF staff or NDA LDAP credentials.
Note that cookie, client IP, form data, and all query parameters except 'action', are stripped from requests before logged to XHGui.