Have you ever hit a bump unexpectedly and had your handlebars try to punch you in the mouth?
Girvin had a solution. They put a pivot and a skateboard bushing in a stem (look close, I had that same bushing on my crappy Tracker trucks back in the day).
One of the great things about cycling is the crazy people who you meet along the way. I’m sure that the designers at Girvin were mad scientists with plenty of personality.
Go Google Girvin: they had some crazy ideas, many of them great. This is just one relic among many from some of the pioneers of full suspension.