We asked camera companies why their RAW formats are all different and confusing

When building a camera, you decide once and then most parameters stay fixed. It would be trivial to just append 1000 bytes for a mostly fixed DNG header to each image.

But how do you test this? While the DNG specification is open source, the implementation was/is(?) not. Do I really need a copy of Photoshop to test if my files are good? How would I find good headers to put into my files? what values are even used in processing?

Maybe the situation has changed, but in the old days when I was building cameras there was only a closed-source Adobe library for working with DNGs. That scared me off.