Michael Ott

<p>It’s often too easy to make edits to your web site that result in a broken link. This plugin will automatically email the web site administrator (or a specified email address) whenever a 404 is encountered, along with a link to the page the 404 originated from. With this knowledge in hand, you can search the page for the problem and either remove or fix it.</p>
<p>Notifications are also triggered by missing media, such as images, video, CSS files and more.</p>
<h3>Support</h3>
<p>Report any issues at the official <a href="https://wordpress.org/support/plugin/404-notify/" rel="ugc">404 Notify Support</a> WordPress page.</p>
<h3>How to use</h3>
<p>Once activated, notifications are automatially sent to the site administrator, or, you can specify an alternative email address in <strong>Settings</strong> -> <strong>General</strong> and look for the <strong>404 Notify email address</strong> field.</p>
<h3>Uninstall</h3>
<p>Deactivate the plugin, delete if desired.</p>


404 Notify

It works as presented. When an internal link leads to 404 you get an email alert. 

Job well done

Get a notification whenever a 404 is encountered on your web site.

Japh

<p>A supplement to the Theme-Check plugin that adds checks for ThemeForest’s WordPress Theme Submission Requirements, and removes checks that aren’t relevant in that context.</p>
<p><strong>The <a href="https://wordpress.org/plugins/theme-check/" rel="ugc">Theme-Check</a> plugin is required for this plugin to work.</strong></p>


ThemeForest-Check

it helps a lot to discover problems in your theme. It's a perfect tool that everyone who is developing a theme for themeforest should have. Great!

very useful

A supplement to the Theme-Check plugin that adds checks for ThemeForest's WordPress Theme Submission Requirements.

404 Notify vs ThemeForest-Check