Currently broken but fixable

This plugin needs updating on line 158 in order to get it to work. replace

$themes = get_themes()

with

$themes = wp_get_themes();

And you’re good to go.

I find it odd that the menu item has been stuffed under the Appearance sub-menu, but as you’re likely to uninstall this once you have tested your site it’s not a big issue. Also it runs some very basic checks for code errors and bad urls. I wouldn’t recommend using only this to check your theme files.