I am working on a RnD project focused on PDF annotating. Annotation sharing, backup, etc. I have seen this couple of lines in other XFDF creating applications.
<pages>
<defmtx matrix="1.333333,0.000000,0.000000,-1.333333,0.000000,1056.000000" />
</pages>
Can someone please explain what is defined by these lines in an XFDF? Any help is much appreciated.
Those keys are not in the XFDF specification, so they are not defined and should be ignored.
The data is custom, vendor specific, data that is only meaningful to the vendor that included it, and would be ignored by all other vendors parsing the XFDF.