Also never heard of this before either. Has been around for some time.
Combat proven. A towed decoy used to fool radar-guided surface-air-missiles [SAM].
ALE-50. Expendable while performing yeoman duty.
"The AN/ALE-50 towed decoy system was developed by Raytheon to protect multiple US military aircraft from radar-guided missiles. The AN/ALE-50 towed decoy system is an anti-missile countermeasures decoy system used on multiple U.S. Air Force, Navy, and Marine Corps aircraft . . . The ALE-50 system consists of a launcher and launch controller installed on the aircraft (usually on a wing pylon), and one or more expendable towed decoys. Each decoy is delivered in a sealed canister and has a ten-year shelf life."
"When deployed, the decoy is towed behind the host aircraft, protecting the aircraft and its crew against RF-guided missiles by luring the missile toward the decoy and away from the intended target."
MORE THAN ANYTHING ELSE CONSIDER THAT THE COST OF ONE EXPENDABLE AND NEVER-TO-BE-USED-AGAIN DECOY IS $22,000 USD!
Nobody ever said war was cheap, did they? F-21 if and when taking to the air to be equipped with ALE-50.