Im just noticing that the JG has an option for level 2. To the best of my knowledge noone has one, but my question is is there any advantage to building it? Most likely its like graviton2 and nothing happens, but Im wondering if it maybe cuts down on recharge time or something?
Thanks in advance

I think someone tested way back. Nothing happens

there is no benefit. The buildings and research do not have "caps" to let you know when you have reached max benefit. However, I would like to see maybe a max benefit of level 3 on this with a 10% decrease in cooldown times on the JG per level, so level 1 would be 60 mil, level 2 54 minutes and level 3 48:36 seconds. It also is an aboslutely great way to resource save fyi. At robotics of 8 you can resource save 4mil/8mil/4mil for like 5 days 13 hours. double the resource/time for JG of 3. BUT its a lot of building points at level 3 to lose should your moon be popped. 5600 pts to be exact.