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 we strip most request metadata for security and privacy reasons. XHGui profiles do not record cookies, client IPs, HTML form submissions, or any query parameters (except "action").