The caliper has a anchor plate that bolts to the back of the "suspension knuckle" (BMW calls it the swivel bearing). According to the BMW TIS, you remove the caliper and the anchor plate as a unit. The torque for these two M12x1.5 bolts is 110 Nm and they are to be replaced with new ones upon reassembly. The two 10mm allen bolts have a locking agent on them and I imagine are designed to be permament (Real OEM shows the caliper and backing plate as a unit).
I looked all this up because I am going to change out my OEM struts for some Koni FSD struts and you drop the swivel bearing and strut as a unit to access the strut for replacement.