Okamoto Hidetaka

This plugin is very simple.Exchang viewport by using jQuery & jQuery Cookies.
IF you installed, your responsive website can show PC view in mobile devices.
Thanks for
Using BlackFlag’s jQuery. 
URI:<a href="http://black-flag.net/jquery/20140408-5086.html" rel="nofollow ugc">http://black-flag.net/jquery/20140408-5086.html</a>
<h3>Arbitrary section</h3>

Viewport Exchanger

There is plugin switching the viewport  of PC view and Mobile view.

wgrivera

A debugging tool that adds a small badge in the corner of the site, showing the current viewport width and height for finding media queries breakpoints and testing responsive website.
Works in real-time, so resizing the browser will also trigger an update to the screen dimensions.
The viewport reporter can be activated or deactivated by enabling or disabling the plugin.

WP Viewport

A debugging tool that adds a small badge in the corner of the site, showing the current viewport width and height for finding media queries breakpoint …

Viewport Exchanger vs WP Viewport