BackupChain doesn’t use the concept of a backup store.
It’s a target folder it writes to, which may be freely rotated. BackupChain continues where it left off last time it wrote into that folder. If you switch off dedupe and compression you’ll see the original file / folder structure and files being reproduced inside the target folder. Probably most of our users love that idea of having direct access to files when necessary and “seeing & controlling” what the backup app does rather than having one big proprietary backup file, which could quickly turn useless in its entirety when there is a single damaged block on disk….