ThemeShock

Custom 404, helps you customize your 404. 
From the dashboard options you’re able to modify the background, the image and the fonts color and style.
This page will show users the last post on your site, so that they may choose to follow one of this instead of leaving your page.
<h3>Features</h3>
<ul>
<li>Customizable background</li>
<li>Several Patterns</li>
<li>Multiple fonts</li>
<li>24 additional images.</li>
<li>5 Different languages</li>
</ul>

Custom 404 Error Page: Unilimited designs and colors

Custom 404, creates a 404 page that is set to the default one of your WordPress installation.
This page is fully customizable from the dashboard.

Andrew Klimek

If the log is long, the latest lines are show at the top to avoid scrolling. Line numbers are shown for reference.
Logs over 5MB do not load until you confirm you are sure, or you can opt to delete the log and start afresh.
Only admins can view (or anyone you give the capability “manage_options”).
Debug Log only works if it’s enabled in wp-config.php. See https://codex.wordpress.org/Debugging_in_WordPress#WP_DEBUG_LOG
Recommended configuration:
<pre><code>define( 'WP_DEBUG', true );// just toggle this line to false to turn off
if ( WP_DEBUG ) {
 define( 'WP_DEBUG_LOG', true );
 define( 'WP_DEBUG_DISPLAY', false );
 @ini_set( 'display_errors', 0 );
}
</code></pre>

Debug Log

View and Delete the debug log from the Tools menu.  Extremely light and simple.

Custom 404 Error Page: Unilimited designs and colors vs Debug Log