I think it would be in the best of interests of the community if we had an optional tag for File Format related questions. It would help reaching out to the community better, for answers.
if VTK uses default Discourse settings then once you established yourself on the forum (by reading and answering posts), you automatically get the right to create new tags.
I have created a file-formats tag. If you point out posts that deserve the tag, post them here and I can add the tag to them.