I am relatively new to this game. I played for a while, a year or two ago. That account has since been lost and forgotten and I started a new account last night and I am finding I have forgotten a lot of stuff about the game. For instance, what some of the various Icon denote. In this case I logged in just a lil bit ago to find this particular Icon, hovering above all of my Buildings. The one displayed below. Can someone tell me what its for, cause I can't seem to find the answer via google. And on the wiki page I only found the definitions of some Icons, but this one wasn't included in that list. Only a pic of it was.
so if someone could tell me, I would greatly appreciate it. Thank you.