Can only add content from root level of package

[Sciemon]

There must be something very simple I am missing here, but I am only able to add content from the root level of my package.
My _quarto.yml looks like this:

quartodoc:
  package: powfacpy
  title: "API"
  source_dir: ./src
  sections:
    - title: API
      desc: ""
      contents:
        - result_variables
        - applications.caching

result_variables.py is a module from the root level and quartodoc finds it when I do quartodoc build. applications.caching.py in the folder applications is not found and results in

File "C:\Users\seberlein\AppData\Local\Programs\Python\Python311\Lib\site-packages\quartodoc\builder\blueprint.py", line 177, in get_object_fixed
    raise WorkaroundKeyError(
quartodoc.builder.utils.WorkaroundKeyError: Cannot find an object named: applications. Does an object with the path powfacpy:applications.caching exist?

Same for any other module that is not on the root level. Can you point me to what I am missing?