Strange, intermittent alarm sound in 1994 Ford Bronco?

I'm looking to identify the source the sound in this video:

It doesn't seem to be connected to anything that I do in the vehicle, and you can hear it cuts in and out mid beep.

Could be an aftermarket alarm that's gone wonky. It's nothing mechanical. And it doesn't sound like the noise that the Bronco makes when you leave your lights on or door keys in the ignition.