Jonathan Desrosiers

Linchpin

Aaron Ware

<blockquote>
Similar functionality has been developed for the <a href="https://developer.wordpress.org/themes/advanced-topics/customizer-api/" title="Theme Customizer API" rel="nofollow ugc">Theme Customizer API</a> and was <a href="https://make.wordpress.org/core/2016/01/28/previewing-site-responsiveness-in-the-customizer/" rel="nofollow ugc">merged into WordPress core as of version 4.5</a>. This plugin will automatically deactivate when you install WordPress 4.5.
</blockquote>
When viewing the front end of the site, a “Responsive” button is added to the WordPress Toolbar. Clicking that will toggle an overlay with your website presented in various sizes for easy responsive design testing.
This can be useful both during theme development, and when writing content to verify it will be presented properly.
This plugin is a heavily modified version of <a href="http://mattkersley.com/" title="Matt Kersley's" rel="nofollow ugc">Matt Kersley’s</a> <a href="http://github.com/mattkersley/Responsive-Design-Testing" title="Responsive Design Testing" rel="nofollow ugc">Responsive Design Testing</a>.

Responsive Page Tester

Gives users with content creating permissions the ability to preview their site in a responsive testbed.

Robert Seyfriedsberger

<a href="http://www.ioncube.com" rel="nofollow ugc">ionCube encoder</a> is an established industry standard solution for PHP encoding. In order to run encrypted files on your webserver, it has have ionCube encoders installed. This plugin checks if this is true and if not, you are given a guidance through the official loader wizard which determines what exactly has to be installed on your server on how this can be achieved (if you are not admin of your webserver, you are given instructions which you can easily forward to your admin).

ionCube tester plus

This plugin helps you to determine if the ionCube loaders are installed correctly on your web server.

Responsive Page Tester vs ionCube tester plus