Not much to say, this is the oil cap and the routing of the oil hoses.
There is a possibility to put the upper half of the cap in 7 different positions to direct the hoses the least resistant way.
"Nice" that it happened to have the BMW colors.
More info with picture "final setup"
You can clearly see on this picture that I have opted to change the water thermostat housing to an solid aluminum housing, instead of the endlessly warping and leaking plastic housing.