Not much to see here, a couple batteries in parallel and a charging controller.
Dig a little deeper, and you'll see how the battery case passes power through to the phone.
A teenie tiny riser connector flipped 180 degrees.
Isn't it cute?
One item worth mentioning, is that this particular battery case didn't pass the OTG (On The Go) connection through to the phone for some reason.
OTG supplies power, so this might be by design.
Now is the time to identify VCC and Ground via the Micro USB connector on the charging controller below... outer-left pin is Ground and outer-right pin is VCC.
Looks like VCC is connected to the pin marked T2.
Rough placement for the charging receiver... looks like we're good to go!