How do I duplicate an edge? I am trying to follow along with this tutorial. I had to put its speed to 0.25 to be able to view it.
In this tutorial it is shown how the author selects an edge and then duplicates it and &quot;scales&quot; it while dragging.
I have taken some screenshots:

How does he do it, and what is this operation called?
Thank you!
It's a bevel, shortcut Ctrl+B.  They then delete the resulting face to leave a gap between the planes.