What looks like a rollbar on the sidecar is a support for an optional soft top that was briefly available for the Sputnik sidecar. The top entirely enclosed the passenger, leaving only a narrow field of vision, forward, through the windscreen. No one liked it. I don’t have the soft top, but the bar makes a nice hand-grip for the passenger climbing in and out of the hack. I threaded a couple of RAM mount balls into it to clamp video cameras to. Currently I am using  them with RAM X-grips to mount a cell phone to the bar for recording.