Green wire is usually ground wire. Do not disconnect ground wire because of the fact that you're risking electric shock unless you know what you're doing.The white tag is a tamper-evident device. I'd advise putting the device back on.
the wire was just sticking out of the housenot connected to anything
almost looks like a padlock seal
Maybe some animal dug up the side of your house.
Can you trace the wire at all? is it hot?