How is the folder hidden?

Question

Windows

Hi all!
The situation is as follows:
There is a certain folder that contains information: three files.
The folder is intentionally hidden from human eyes in order to protect the files contained in it from being copied and transferred to each other.
On the desktop - a shortcut to the executable file of the program, through which files in that folder are opened and viewed. I open the program, in the properties I see the location of the files. Through “run” I get to the folder, but it is empty. (Looks empty). The folder properties say that "0" space is occupied, "0" files are contained, and generally get out of here.)
Well, through “cmd” I delete absolutely all the attributes of the folder, assuming that it can be system / archive / hell knows what else. Attrib does the job, but the folder remains as impenetrable as it was.
Yes, the display of hidden system ones is enabled in the system. I run it with superuser rights.
By the way, from the command line, with the help of the good old “litter”, all files from the folder are quietly copied anywhere.
Total does not see the folder. Far was not at hand, unfortunately.
I'm very curious how such a "copy protection" is made. Please tell me who knows.
Thank you in advance.