I am stuck while following this tutorial https://www.youtube.com/watch?v=28AlRLMlqW8&t=4251s&ab_channel=FlyCat
At 0:33. The youtuber highlighted the vertical line in the middle of the hexagon and did something to make it split into 2 vertical lines.
It happened pretty fast in the video so i took some screen shots too.
Can someone please tell me how he/she did it?
Thanks in advance.