I tried the app and I did notice the first screen is "Select Storage Location" after you try to add a new backup and it lists: local dir, aws, gc, azure, b2, s3, sftp.
So I indeed guess it can as well be used as restic frontend (but I am not really sure to what extent it uses restic and whether blobbackup is just a gui/skin for restic)
I think you may have tried our original app (the original folder in the github repo). I need to clean up the Releases page. That version used a custom backup engine and allowed backups to a number of storage providers (S3, B2, SFTP, etc).
The new app uses restic as the backup engine and only supports backups to B2 right now. Sorry for the confusion.
Because that’s where my restic backups go to (natively).