You are probably after the broadcast wave format: wikipedia
There are several extensions noted. I used to work on a place that made heavy use of the BEXT chunks, but I wasn’t involved in reading or writing, so I have no deeper insight.
Here some communications about that topic:
So the first thing would be to figure out the exact name and type of metadata you are looking for… Maybe even jump in using a HEX editor, if all else fails…
