Checking out the shapesheet of container shapes (no list) that have a nice heading and design, both their group and subshapes and I must say: wow I did not realize how complicated these shapes are internally!

One of the subshapes (the 'background' shape the Belt group shape surrounds) has five geometry sections and a big user section filled to the brim with formulas.
Since I am using it with just a flat background it seems to be complete overkill, but I probably am not realizing all the cool things group shapes can do.