When you click Files in the AdminCP the first page you see is the Attachments screen which lists all file attachments Suite-wide.
File attachments on this screen only include those files attached to a post-field. This would be any attached file to any content that members type in the editor. It does not include application-specific files such as Gallery images, Downloads files, member photos, and so on.
You can quickly delete attachments on this screen or use the magnifying glass icon to see where a certain attachment is being referenced. Members can upload ones but embed an attachment in multiple posts so it's a useful way to see how a member is using their attachments.
You can also quick search a file name or open up advanced search options. Note that downloads do not work for images as they are not downloaded but simply viewed in the post itself.