What is counted as subpages?

Pages and posts

WordPress differentiates between pages (static “one-off” pages like ‘about’, ‘contact’, ‘privacy policy’ etc.) and posts (actual blog posts).

The Cookiebot scanner scans your website in-depth to identify all cookies and other tracking technology in use. Since blog posts can also contain cookies and trackers – for example in images or in embedded videos – we need to scan not only the static pages but also all the blog posts. For this reason, the number of pages according to WordPress and the number of pages according to the Cookiebot scanner will likely differ.

You can read more about WordPress’ definition of a page vs. a post here: https://www.wpbeginner.com/glossary/page/

Images

Some users mistakenly think that the Cookiebot scanner counts their image files as subpages, thereby increasing the number of subpages and resulting in the domain not being eligible for the free subscription. Cookiebot does not count image files as subpages. Depending on your theme, WordPress may automatically create real pages for content placed in your media library. These pages are called Attachment pages. Because these pages can also contain cookies and online trackers, Cookiebot scans and includes them in your page count.

To disable the Attachment page feature in WordPress, please see the following guides:

https://themeskills.com/disable-media-attachment-pages-wordpress/
https://www.wpexplorer.com/disable-image-page/