Instead of or in addition to the current positional information, have the text that was highlighted as an annotation appear in the xml file of annotations in the docdata directory. Reproducible: Always
Sorry but no, the .xml file is there not for information exchange thus adding the text makes no sense in that regard.
Currently the xml file is the only way I have of accessing the note annotations I am making. Does this mean that this functionality is not going to be supported in the future?
No, the xml file is not going away, we're just not adding unneeded data to it as the one you are requesting.
Unneeded data? I need it. How do I get it out of the pdf?
You can read the coordinates of the highlighted rectangles from the xml file, and use them to extract the corresponding text from the PDF file. I think you can use okular's own API to do that, have a look at Page::text(RegularAreaRect *) (http://api.kde.org/4.x-api/kdegraphics-apidocs/okular/html/classOkular_1_1Page.html#a11ab0f2abe5c1e760c046a33fd5393f3). You can also directly obtain the list of the annotations using okular's API instead of parsing the xml data.