FRBs are the RF noise left behind by an enormous release of energy at a great distance. Probably a teenager letting loose on the warp drive in a deserted part of the universe. We just happened to be bore-sighted on his exhaust axis.
Bursts of Alien Radio TransmissionS.
BARTS.
Some are louder than others
Mega BARTS.
Variations:
Blue Darters and Twizzlers.
We are in the galactic boonies!