Almost perfect

This plugin is simple, works as advertised and is excellent for finding short codes in content, including CPT.

It will also find where the short code is defined in the code (plugins, theme etc)

The one error it misses is if shortcodes are embedded in Custom Fields. As an example we use an advanced custom field to allow clients to add a contact form to a page by entering the short code into a field. This is not found by this plugin.