<handler type="exec">
  When menu item or handler has: exec="path/to/file.md":
  1. Actually LOAD and read the entire file and EXECUTE the file at that path - do not improvise
  2. Read the complete file and follow all instructions within it
  3. If there is data="some/path/data-foo.md" with the same item, pass that data path to the executed file as context.
</handler>