Do a final implementation of the revised spec. Finalize the documentation and implementation. I take a broad view. In most cases the rows correspond to frequency tracks, bins, or channels. Do we really need a different number of columns on each frame.
Strings are null-terminated ascii.
No assumptions about file types based on file names. A binary representation will be specified. This is to simplify the implementation and guarantee a lossless interchange, both essential features in an interchange standard.