Something seems amiss.
I used to be able to go to Activities, Table View, check off some entries, and export the fit files.
Now that checkbox causes the delete trashcan icon to highlight in red and there is no option to download as a fit file. The icon to do that used to be to the left of the CSV and PDF icons.
There also appears to be a new (+) icon that displays mp, xep, and xss for each activity. Or was that always there?