What’s the syntax described in the docs?

  package_data =
      mypackage = templates/*.html static/css/*.css

or

  package_data =
      mypackage = templates/*.html
      mypackage = static/css/*.css

?

On a related subject, I think the new resources system should obsolete data_files and package_data.  Putting files in arbitrary, OS-specific places (data_files) or alongside the Python files (package_data) was wrong, let’s move away from that.