Originally Posted by Montauk
I couldn't figure out the purpose of this plastic thing sticking out on the left side above the cylinder
From image posted by EJ_92606 (just realized that you are in my backyard, I am north of Hwy 5), this means, that the thick cable is carrying fuel and not fuel vapor. Leaving it exposed to outside prankster to cut the cable. Further, it seems that they fastened it with 1 screw.
But the good thing is that they placed it where it would not easily break through accident of some kind. I hope extreme heat from the cylinder do not cause problems with the cable while it sits on top. It looks like it is touching the cylinder.