It seems that there is no documentation around the actual contents of the Bulk Grade Download CSV.
The feature is documented
but the contents are lacking any sort of explanation of the contents of the file.
Look at "220.127.116.11. Interpreting the Grade Report" and "18.3.6. Per-Learner Interventions Report", those each contain some amount fo breakdown of their respective files.
Add something like this for the Bulk Grades CSV Export
After updating, work with Support to validate the descriptive language. Likely, Jen Akana.
describe the data dictionary for the download file. Utilize language for end-users.
Styling to match the surrounding sections.
See #Bulk Grade CSV for existing, great documentation.