I just finished creating a Node.js script to merge Intervals Streams.csv with Calibre Bio CSV: https://storage.googleapis.com/intervals-icu-images/attachments/bcb3e5c4-8777-40ff-8b32-df1335c6969c. It’s easily modifiable to process other stream-based CSV files as long as they have time and heart rate fields.
With the new Intervals upload functionality, it just works. Download and upload activity streams CSV - #19 by pepe. David made this easy.