Are you referring to third-party change management tools like Microsoft TFS etc.? I think you need to provide some further clarification in order to get some responses, as I was not sure to what you were referring, and I have no idea what QDF is either, that is not an acronym we use, or at least of which I know, so it will help if you can clarify that too.
I believe some customers make use of the Project Files:
Others just keep the empty QVW file backed up somewhere along with the QVD files, but in most cases things can be recreated provided the backend data that was used to build them in the first place is still available. About the best I can offer, if you can further clarify what you really want, I suspect you may get some further responses.
To help users find verified answers, please do not forget to use the "Accept as Solution" button on any post(s) that helped you resolve your problem or question.
I now work a compressed schedule, Tuesday, Wednesday and Thursday, so those will be the days I will reply to any follow-up posts.