Codepress

It shows a tab with diagnostic info about your site and settings. You can use this plugin when you have a support issue.

Admin Columns Diagnostics

This plugin assists you with support for Admin Columns.

ChubbyNinjaa

Do you get frustrated trying to work out what the template file you’re editing is? Ever had to echo/print some text to see if WordPress is picking up the file you expect it to?
If yes, then give this plugin a try, it simply adds a handy dropdown at the top of the admin bar giving you the ability to quickly see what theme template file(s) is being used, as well as what other files are being included, from themes and plugins.
Never get frustrated with creating child themes again, using Template Debugger you can generate a new child theme based on one of the installed parent themes, and Template Debugger does all the leg work! Just fill out the input fields and Template Debugger will create the theme directory, add in the style.css and functions.php
Plugin features:
<ul>
<li>
Quickly find out what template file(s) are being used
</li>
<li>
See where they’re included
</li>
<li>
See what plugin template files are in use
</li>
<li>
Create new page templates from post editing screen
</li>
<li>
Create child themes from a parent theme
</li>
<li>
… Got an idea for a feature?? Cool! Drop me a message in the support forum
</li>
</ul>

Template Debugger

It make the process of theme customization so much easier, I use it on every WordPress website I develop !



A must have

useful

Intended for Developers: This template debugger helps you identify what template files are being used on the page you're viewing.

Admin Columns Diagnostics vs Template Debugger