dcmake.exe is a command line utility that allows to convert Adobe XD (soon will be available converter for Figma) to the DC XML format.
dctool.exe is a comprehensive application that allows you to create XML design documents from scratch. You can also upload Adobe XD there through the Import menu and modify it.

dctool.exe is still under development and many editing functions are either disabled or do not work correctly. But in general, these programs can do the same:

dctool.exe - Import From... Adobe XD "AdobeXDDocument.xd" - Save As (Save Components As) "AdobeXDDocument.design"
dcmake.exe - "dcmake.exe -i AdobeXDDocument.xd -o AdobeXDDocument.design -c -f online"