Black Bar free WordPress plugin

Black Bar is an unobtrusive Debug Bar for WordPress developers that attaches itself to the bottom of the browser window. It is a rewrite of blackbox-debug-bar by Grzegorz Winiarski which appears to be abandoned as it has not been updated since 2013. How it helps you with development: Displays any PHP errors that occur when loading a page Displays executed MySQL queries and the time it took to execute each query Displays the loaded template files of the active theme Inspect global variables (COOKIE, GET, POST, SERVER, SESSION) Use the Console for debugging your plugins and themes Use the Profiler for measuring the performance of your plugins and themes