Tesla calls these "Mobile Superchargers," but the "Mobile" part of it is kind of like today's mobile homes. It is factory built and transported to the intended site. There it is (semi)permanently connected to a 208-Volt or 480-Volt, 3-Phase existing distribution panel.
The "Mobile Supercharger" contains one Supercharger Cabinet that services two Supercharger Stalls or Pedestals, one on each side. Because most of these installations are to existing 208-Volt 3-phase service, they are limited to 90 kW, shared between the two stalls. A 480-Volt connection will provide 120 or 135 kW out.
In the picture below, you can see the two pedestals serving Stalls on either side of the Supercharger Cabinet, the Supercharger Cabinet in the middle, and the conduit carry the power to the Mobile Supercharger going out the back.