It only copies that tabs of the particular window you are in. I have over 15 windows open. I will need to repeat this action 15 times. Very impractical.

Additionally, it does not leave any space between URLs and I'm having trouble figuring out where each one ends.

A little better design, like having an empty line between them, would have solved this problem.

To sad they didn't do these two points.
I'm going to remove it.

Unfortunately, it does not work as intended as it does not copy anything.

I would love to use this, but clicking the button does not copy anything to my clipboard, and the author has provided no means of contact or bug reporting.