This is a slightly modified standard Flutter app with a build.sh bash script that generates docset documentation for the Flutter app.
You can copy over build.sh for your own Flutter project in the root directory and the docset should end up in doc/yourapp.docset.
Docset is used by Dash and Zeal among others.
This script uses dashing, jq and yq. Optionally, python3 is needed with the Pillow package for resizing the image based on the iOS AppIcon of the current app.
You can install them using:
brew install dashing jq yq
# Optional for image resizing:
brew install python3
pip3 install Pillow