*What WordPress Theme Is That* is a free online tool designed to help users discover the WordPress theme a site is using, including both the parent and child themes. This platform is particularly useful for developers, designers, and curious users looking to replicate or understand the design choices of a website. In addition to theme detection, it provides insights into the active WordPress plugins on a site, which can be crucial for understanding its functionality. This tool is user-friendly and offers valuable information without requiring any subscription or payment.