Following some previous discussions, @Remi-Gau commented on our draft that we should re-tool our definition of raw data to be that which is output in a non-BIDS source, while derivatives are data that are derived from a valid BIDS dataset (x).
In that sense, we need to consider what to do when a proprietary data software calculates something we had previously considered to be a derivative (e.g. heart rate), and how to allow our naming conventions and meta-data to reflect this possibility.