2001 S60 Battery drain from under seat module

[chv3ch]

I was looking for cause of 300 mA drain on battery. Yanked out rear seat to follow battery cables and found strange module. Anyone know what this is? Does not look like factory equipment. Perhaps an aftermarket alarm system?
It is a Motorola part number 19052WNM8D.

Unplugging the cables removes the 300mA drain.

[RichCrewe]

Googling for 19052 leads to a "Cell Radio Accessory" on E-bay. Probably a '90s in-car cell-phone.