Almost every time you save a web page from a web browser to your local computer a PAGENAME.html (or .htm) file is created and a folder named 'PAGENAME_files' that contains resources specific to that page.
If you copy/move/delete either the folder or the .html file Windows automatically does the same operation the other file as well.
This behaviour also happens if you create a file named 1.html and a folder called 1_files.
How does this link happen? And why does it work only with web files?