Development mule

Porsche 918 Spyder development mule in Monaco (2013)
A camouflaged pre-production BMW X5 mule near Munich (2013)
Honda Civic mules in California (2015)
Hyundai Grandeur mule in South Korea (2022)

A development mule, also known as test mule or simply mule, in the automotive industry is a testbed vehicle equipped with prototype components requiring evaluation. They are often camouflaged to cover their designs.