I note that - with the Sentinel-1 Toolbox Kit Module [6.0.3] activated - the ‘Metadata’ folder in the Product Explorer contains and Sentinel-2 products contains an ‘Abstracted_Metadata’ node that contains non-S2 fields:
yes , this is known. Abstracted Metadata gives access to common SAR metadata in a standardised way. It is created on the fly, unfortunately to all products.
We plan to generalise Abstracted Metadata in a way that it is useful for all sensors. This is on our roadmap. Might be implemented in the next ~12 months.