Just a wild guess but does it fit nicely on one of the tube connectors?  I'm guessing it is to allow a filtered bypass of sorts if you were to unplug the connector and slip the filter tube on one of the tube fittings.  Not sure exactly why they would do this, but if it fits tightly it seems like too much of a coincidence.
		 
		
		
		
		
		
		
			
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				70Z28 04B Norwood Forest Green-white Stripes  Black DeLuxe Interior 
Owned since 1978 - First Car
			 
		
		
		
		
		
	
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