Straying a long way from the topic of the thread, but:
True, they’re not well documented by the camera makers. However they are very transparent and very well understood; they are all (or virtually all) built on the TIFF model. See this explanation by Bogdan Hrastnik on the ExifTool website for more.
Re DNGs, as mentioned in another thread, the format never really took off in the way that it was envisaged and personally I can’t see any good reason for using it (except as a better native alternative to JPEG on your mobile phone). If you do use it, at least learn the pros and cons.