Hole diameters and slots are always expressed in finished size, the board house choses a proper drill size to account for plating etc.
Milling tolerance: 0.2 mm (Implies board edge clearance > 0.2mm)
Plated slots: size >= 0.5 mm, length >= 2*size
Openings in solder mask smaller ⇐ 0.4 mm is difficult