We have found 2 software records in our database eligible for .dng to .xmp file format conversion.
dng to xmp conversion is not possible in the file conversion sense, simply because XMP format used by Adobe does not contain any graphics data, just metadata for existing picture. Thus when you export DNG file for JPEG for example, the metadata can be saved in the separate .xmp file.
XMP format is used in Adobe software only and you can find some articles that cover its useage on the Internet, they are not made through file conversions though.
DNG
A dng file extension is related to the Digital Negative (DNG) RAW digital image file format developed by the Adobe Corporation. It is used to store digital RAW pictures captured by digital cameras and DSLRs (Digital Single Lens Reflex cameras).
XMP
An xmp file extension is related to the Adobe Extensible Metadata Platform. An xmp file stores metadata about photos like camera type, date, image dimensions etc.