It collects some useful information about the website (number of posts, server environment, active plugins…). If you need for example to give a quotation to restyle or optimise a website, without the need to log in to the backend, you can ask to install this plugin and give you the collected information. The actual version collects the following data: Home URL WordPress Version WordPress Multisite: Yes/No WordPress Debug Mode: Yes/No PHP Version MySQL Version Server software (e.g. Apache) Must Use Plugins Active Plugins Current Theme Theme Version Child Theme: Yes/No Number of Post Types Number of queryable Post Types Total Number of posts (any type) Number of posts for each post type Site Health summary User Agent used by the user who give you the collected information As you probably know the Site Health already gives a lot of information, but it includes too sensitive information as database name and database username. And most of all, it misses information like number of pages, number of posts and custom posts. However if you think the information included in the Site Health page are ok for your purpose, of course, you don’t need to install this plugin.