When in the Garmin Connect Developer Program, I use to be able to use the Data Generator, Data Viewer and more to test some api work. However it now fails because I cannot select a SummaryType. Interestingly enough the field name is in the form but no way to select. I theorize it was being used "Request Signing" but was not needed, so someone tried nuking it but it killed all the other tools.
I would put a picture but this bug report forum tool seems to also be buggy