Hole at the back of the Nether hub

Subject: Hole at the back of the Nether hub Sun May 12, 2013 3:57 am

First topic message reminder :

I was in the hub to look around before starting to head to Spine's place to look at his tree until I noticed a hole in the back. I started wondering why it's there. I took a look at it and saw that it's heading towards the green house at the path to the village. [Only admins are allowed to see this image]
I asked Pine about it since he's planing to make a tunnel near the hole to his Nether portal someday and he said that he doesn't know why it's there. Does anyone know why it's there in the first place?