Now that MP3Tag supports WAV/RIFF, I would like to request that CART chunk capability be added in addition to INFO.
Cart is a tagging format used heavily in broadcast. It would be helpful in many broadcast facilities to have a tagger that could read/write these chunks.
The chunk format is fixed length, fixed field length, so it should be relatively easy to parse and construct.
Here is the Cart chunk information dialog from an old version of Adobe Audition: