Directory named "Qml" does not appear in a qtquick project

I create a new project (other/qt quick prototype). In the project directory I created a
subdirectory name "Qml". When I look at the project in Qt Creator/editor is see all
of the other directories listed except "Qml".
I tried to find documentation that explains why this directory is not listed, but I cannot
find any such documentation.

It seems this is an undocumented assumption. I have no idea what would happen if I
placed anything in that directory. It seems this might be a source of future errors.
I considered all undocumented assumptions as potential sources for errors.

It seems reasonable to expect to see this restriction somewhere in the documentation.
It would be nice if all "assumptions" were laid out in one place, so that we as
designers/composers could learn all of these rules by looking in one place. Stumbling upon
them is not nice, and leads to more debugging and less productive time.