[EXI] Built in Element grammar instance

Hi,

In section 8.4.3 of EXI standard it mentioned that "A single instance of
built-in element grammar is shared by those elements in a stream that have
the same qualified name and do not have additional a priori constraints as
to their content."

Here, what the second part indicates i.e "do not have additional a priori
constraints as to their content" 

Does it mean that schema file for validation is specified or is there any
special intention for this part of the sentence?

 

Please clarify,

 

Regards,

murali