Notes:
*I am assuming "application number" in the patent code means "There seems to be filing number", because the word "filing" appears nowhere in the code, and there is already a different number, under the "publication reference" header, that seems to be referring to the patent number. It's likely that the number under which the patent is internally filed is called "application number", and appears under the header "application reference", and that the (publicized) for each patent number appears under the header "publication reference"type. There is also an example no examle xpath for Application_Number on [[Equivalent_XPath_and_APS_Queries#Query_Equivalences]], and none for filing number. I'm leaving filing number blank for now. *An example xpath for a certain block of code from granted, v4.5, plant:
<us-bibliographic-data-grant> <publication-reference> <document-id> <country>US</country> <doc-number>PP027502</doc-number> <kind>P3</kind> <date>20161227</date> </document-id>