There is a 90° flanked cove bit, and a normal cove bit.
The 90° flank cove bit is made to cut corner radii with blending flank on the top and upstand in one past. A special 45° jig is required to hold the router at 45° to the vertical.
The normal cove bit has an extended shank to cut coves into the upstand corner.
This is the profile produced by the normal cove bit