What is the difference between (., .., ...) in the html file path?

From empirical testing with my own web server, there is nothing special about ...

This is just a valid directory name that may exist in my root directory.

However, as ..

and .

, and all the other ways to Unix, starting with .

, are not displayed when you run the command ls

instead ls -a

.

Note. As @EdCottrell pointed out, this is a somewhat suspicious choice of directory name, so it could be a symptom of an attack.