This looks like a plain list of files and folders—much like the File Explorer on your computer. When people search for "parent directory," they are looking for these raw lists of files, which often include images, videos, and documents that were never meant for public eyes. Why "Private" and "Exclusive" Images Leak
Understanding the "Parent Directory Index of Private Images Exclusive" Loophole parent directory index of private images exclusive
Place an empty index.html file in every subdirectory. This looks like a plain list of files
Web servers like Apache or Nginx often have "Options +Indexes" enabled by default, which tells the server to show the folder contents if no homepage is found. which often include images