A report result document can be opened by a link like:
https://.cumulocity.com/inventory/binaries/
e.g. https://mytenant.cumulocity.com/inventory/binaries/5575486
With that link you get all:
https://.cumulocity.com/inventory/binaries?pageSize=200&orderBy=lastUpdated&contentType=text/csv
This outputs for each report a row like this:
{“id”:“5575486”,“lastUpdated”:“2018-11-26T10:15:07.843Z”,“name”:“test export_managedObjects_2018-11-26T10:15:07.800Z.csv”,“owner”:“service_cep”,“self”:“https://mytenant.cumulocity.com/inventory/binaries/5575486",“type”:“text/csv”,“c8y_IsBinary”:“”,“length”:2484,“contentType”:“text/csv”}],“statistics”:{“currentPage”:1,“pageSize”:200,"totalPages”:1}