Debug Bar is a plugin from WordPress' creators themselves, Automattic Inc. As the name implies, it's a plugin for debugging WordPress installations and improving a site's performance.
It works by adding a special option in the WP admin bar, which drops down a debug panel for showing information from WordPress' underbelly. Debug Bar gracefully presents details about memory usage, database queries, HTTP requests and current cache state.
Debug Bar can be used anywhere on the site, including the backend, to detect slow loading pages and see what's really happening and where the problem may be comping from.
A blog's editor won't find this info useful at all, but webmasters, plugin and theme developers will simply fall in love with the introspective this plugin provides.
The plugin is available on the WordPress plugin repository, making it easier to install via WP's built-in plugin installation tool.
Download Debug Bar from our Scripts section here.