Corrects badly formed XMP metadata and optionally removes it, if it cannot be fixed, ensuring that PDF files can be made PDF/X-4 compliant.
XMP metadata is descriptive information about the file embedded in the PDF, for example the name of the author, keywords, copyright information... XMP refers to labeling technology that is used, i.e. Adobe's Extensible Metadata Platform. You can view the XMP metadata in a file's Document Properties in Acrobat (Click the Additional Metadata button, then select Advanced).