This branch/clone/whatever git calls it of the official Facebook GUI does a few things:

• It includes a header.php document you can use with PHP's auto_prepend_file directive. It sets up profiling by initilizing a few variables, and setting register_shutdown_function with the footer. Once started profiles are done when requested (?_profile=1), or randomly. Profiled pages display a link to their profile results at the bottom of the page (this can be disabled on a blacklist based for specific documents. e.g. pages generating XML, images, etc.).
• For tips on including header.php on an nginx + php-fpm install take a look at: http://www.justincarmony.com/blog/2012/04/23/php-fpm-nginx-php_value-and-multiple-values/
• The GUI is a bit prettier (Thanks to Graham Slater)
• It uses a MySQL backend, the database schema is stored in xhprof_runs.php
• There's a frontend to view different runs, compare runs to the same url, etc.

Key features include:

• Listing 25, 50 most recent runs
• Display most expensive (cpu), longest running, or highest memory usage runs for the day
• It introduces the concept of "Similar" URLs. Consider:
  • http://news.example.com/?story=23
  • http://news.example.com/?story=25 While the URLs are different, the PHP code execution path is likely identical, by tweaking the method in xhprof_runs.php you can help the frontend be aware that these urls are identical.
• Highcharts is used to graph stats over requests for an easy heads up display.

Requirements:

• Zlib library in PHP: http://php.net/manual/en/zlib.installation.php (Used to compress serialized data)
• Database backend
• MySQL, or MySQLi for data storage fully supported
• Support for SQL Server now in beta stages #jumpInCamp

Work that we're still doing:

• The aggregation functionality is ignored completely
• The code is... a mess. Deadlines do that to you, we're working on it
• The default table schema isn't indexed all the places it needs to be
• Easier ways to diff URLs