Samsung Battery Mystery Solved - most likely.
Few Samsung batteries have 7 lines of text, so I'm pretty sure this is the one.
Note the 'features' in pic 2. This appears to be an NFC antenna that is openly advertised by the battery mfg. (Which is usually 3rd party Chinese crap.)
So the big questions for anyone who knows anything about Samsung (or other phones) and NFC – These batteries have 4 connections. Is NFC communication part of the specifications for these? Is there an above board abuse of the battery standards that enables NFC communications that is accepted in the industry?
NFC operates at 13.56 MHz. Pic 3 is an NFC antenna from a different source.
I'm pretty convinced this is just an asshat who thinks his NFC antenna was being used by the FBI to access his illegal shit.
That being said, these extra antennas are actually rather scary. God only knows what the phones are doing.
Also, special note for those who don't know (because most don't): EVERY cell phone has at least two CPUs. The radio chips for cell phones run their own operating system and are exploitable. So no matter what you're doing in the other part of the phone, an exploit to the radio chip (which there are many) can ruin your day, so to speak.
I'm VERY careful with the very old phone I have and very aware of just how dangerous these fucking things are.