Michael Torbert

This plugin is great for someone needing to debug their own or another person’s WordPress site. It will collect and display and/or send debug information to an email address provided by the user. 
This is helpful for plugin or theme authors wanting to debug user’s sites.
Some features:
<ul>
<li>Displays system information</li>
<li>Emails system information</li>
</ul>
<h3>Arbitrary section</h3>
You may provide arbitrary sections, in the same format as the ones above. This may be of use for extremely complicated 
plugins where more information needs to be conveyed that doesn’t fit into the categories of “description” or 
“installation.” Arbitrary sections will be shown below the built-in sections outlined above.
<h3>A brief Markdown Example</h3>
Ordered list:
<ol>
<li>Some feature</li>
<li>Another feature</li>
<li>Something else about the plugin</li>
</ol>
Unordered list:
<ul>
<li>something</li>
<li>something else</li>
<li>third thing</li>
</ul>
Here’s a link to <a href="https://wordpress.org/" title="Your favorite software" rel="ugc">WordPress</a> and one to <a href="http://daringfireball.net/projects/markdown/syntax" title="Markdown is what the parser uses to process much of the readme file" rel="nofollow ugc">Markdown’s Syntax Documentation</a>. 
Titles are optional, naturally.
Markdown uses email style notation for blockquotes and I’ve been told:
<blockquote>
Asterisks for emphasis. Double it up for strong.
</blockquote>
<pre><code><?php code(); // goes in backticks ?>
</code></pre>

WordPress Debug

Displays and emails system information for debugging purposes for easy debugging of your own or a client/user site.

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.

WordPress Debug vs Template Debugger