When I set up my backend storage with Google Drive I downloaded the gcd-token.json file from Google and put it in a temporary directory on my NAS. Then I pointed Duplicacy Web to this file. I was fully expecting that it would read and interpret the content of the file and store it encrypted inside the container (and indeed within the container there appears to be a GCD related configuration).
However after I deleted the gcd-token.json file, my backups started failing and i had to put that file in a more permanent location, delete and recreate the the Duplicacy storage.
It would be great, if Duplicacy would actually embed that file into its own configuration, ideally encrypted, like the rest of the credentials. And if other storage backends need a similar credential file, it would be a good behavior to have with all credentials.