yes, I mean… no, I mean “kind-of” 
the thing is that the contour component outputs a tree that is grouped (branched) by section, so the input geometry data tree is just relevant for the order in which the contours are generated
if the geometry input of the contour component is just plain-flattened, then the output tree will just be A;B so a Trim tree would work exactly like a pathmapper with {N branching} → {N branching -1} = {A;B} → {A}
the initial geometry tree structure could anyway be reinstated the very same way
by the way: I did get there with my fingers first… lots of clicking then it actually made a lot of sense 