All the containers and text Texinfo tree elements not handled with command tree elements have a type associated. As for commands tree elements, they can have an opening function and a conversion function registered for a type and used. Some types may need more specific information too.
For tree elements that contain text, a text type is used
to select the formatting functions, irrespective of the actual type of
such a tree element. The text type does not exist in actual
Texinfo tree elements.