The green "Goo" is dripping from the far left of the bar code sticker on the bottom of the shelf, in between the 5th. and 6th. top fuses I think. And directly above the top 3rd. fuse if my Wal-mart specs are seing things the right way.

Maybe there is or was a power supply mounted above this equipment that had batteries or just a leaking power supply.
It did not have to be directly above the equipment either, the fluid could drip down onto and flow down the jumper wires and onto the equipment below.

Let us know what you find out if you do please.