So I did a little googling and came across this:
One port is a normal Displayport 1.4, but the other one is a Displayport 1.4 MST (means: Multi Stream Transport) Info from here: https://www.displayspecifications.com/en...

I didn't know what MST meant either, so I did some research and found this: https://www.computerwoche.de/a...
Quote:
"These monitors have a display port input and output. The first monitor is connected directly to the notebook or PC, the second monitor is connected to the output of the first. ... MST now allows the computer to drive the additional monitors as separate displays."

So you can connect two or more monitors to a computer with one cable. What is not quite clear to me is where you would use something like this, a laptop usually does not have a display port and a normal PC usually has several outputs.

I hope I was able to help, have fun ;)

Thank you for the detailed feedback.