In 1968 the "Breeze Way" roll down back window that Mercury and Lincoln made famous in the late 1950's was faded out due to new safety standards, so FoMoCo came up with this design shown in the 1971 Lincoln Mark III that pulls the inside air out through the back deck and is sucked out through the grates behind the back glass.
Worked really well and eliminated the wind noise of "wing window" vents or cracking the door windows.