ROS2 design - resource directory

edit

I'am interested in the answer as well, we can see that it is present in the trivial workspace example from the ROS2 Tutorial package but without further information.

And the function ros2 package create automaticaly generate a ressource folder as well as create an "installation setup" for that file even though it is empty.

 data_files=[
 ('share/ament_index/resource_index/packages',
         ['resource/' + package_name]),
 ('share/' + package_name, ['package.xml']),],

And if I try to remove those lines, I get :

[1.114s] WARNING:colcon.colcon_ros.task.ament_python.build:Package 'XXX' doesn't explicitly install a marker in the package index (colcon-ros currently does it implicitly but that fallback will be removed in the future)