Created attachment 36001 [details]
A slideshow which embeds word documents

In the last commoncrawl regression tests we saw a parsing exception to an embedded word document inside a slideshow. The XSLFRelation.WORKBOOK uses the general relationship type "http://schemas.openxmlformats.org/officeDocument/2006/relationships/package" for embedded resources, but those can point to various non-/office types and so shouldn't be parsed by POIXMLFactory.createDocumentPart() by default.

I've already implemented a switch based on the used file extension, but this would lead to further problems when writing the document, therefore I simply ignore the "descriptor class" and return the general POIXMLDocumentPart in such cases.