Greg Winiarski

BlackBox is symfony like unobstrusive debug bar attached to the top of the browser window.
How can it help you with development: 
1. instantly inspect global variables (GET, POST, COOKIE, SERVER) 
2. debug both frontend and admin area 
3. executed MySQL queries and time it took to execute each query (useful for finding slow queries) 
4. profiler for measuring performance of your plugins and themes 
5. errors occurred when loading WordPress page

BlackBox Debug Bar

Immediate feedback on a great majority of errors. Added a conditional red background to the Errors, and with this modification I have never miss even a notice anymore.

Thank you very much!

Essential plugin in my developer toolset

BlackBox is a plugin for plugin and theme developers. It collects and displays useful debug information (errors, executed queries, globals, profiler).

Oleg Butuzov

Debug Bar Rewrite Rules adds information about Rewrite Rules (changed via filters) to a new panel in the Debug Bar. This plugin is an extension for <a href="https://wordpress.org/extend/plugins/debug-bar/" rel="ugc">Debug Bar</a>, but it is also can work in standalone mode (as admin tools page). Note: this plugin not able to track <code>add_rewrite_rule</code> function calls, for a reason this function is untraceable.
Once installed, you will have access to the following information:
<ul>
<li>Number of existing rewrite rules</li>
<li>List of rewrite rules</li>
<li>List of available filter hooks that can affect rewrite rules.</li>
<li>List of filters that affects rewrite rules.</li>
<li>Ability to search in rules with highlighting matches.</li>
<li>Ability to test url and see what rules can be applied to it.</li>
<li>Ability to flush rules directly from debug bar panel/tools page.</li>
</ul>

Debug Bar Rewrite Rules

This plugin makes it so easy to debug and even discover WP rewrite rules. Thanks a lot!!

Amazing plugin!

Debug Bar Rewrite Rules adds a new panel to Debug Bar that displays information about WordPress Rewrites Rules (if used).

BlackBox Debug Bar vs Debug Bar Rewrite Rules