This has an impressive envelope for a mill and is used in the manufacturing process of wind turbine blades. I initially guessed this was for composite trimming operations but the manufacturer lists the machine for work with “polystyrene, resins and fibres.” This is possibly used for form or blade core manufacture?

This is a high-rail gantry style mill which can make part loading more difficult due to the mill legs but ultimately decreases the moving mass of the machine. The numbered assembly hanging off the gantry appears to be a tool changer.

Manufacturer link here. No information on tolerances.