I'm working with XML from the USPTO bulk download which provides weekly downloads of XML of published patent grants. I'm using this documentation to understand the files.
I'm having trouble understanding the significance of the
us-field-of-classification-search element (see page 26 in the referenced documentation). It seems to be repeating fields that have already been provided, specifically, it seems to be repeating classification information provided by other elements such as those beginning on page 11 of the aforementioned documentation.
What is this element actually providing?