"Known Hosts Data" on Hetzner Storagebox?

Hi there,
i want to use the Hetzner Storagebox over SFTP.
The config aks me for “Known Hosts Data”, what does that mean?
Why does it not work with only user & password?
Thanks for info.

Alex

It works now, see KopiaUI + SFTP is not Windows friendly - #3 by santacruzskim

It would be useful if a note on this would appear in the GUI.

Hetzner’s Storagebox is great if you need traditional storage but IMO it does not work well with software like Kopia. I have tried to use Kopia (and restic) with Hetzner’s Storagebox because it is a great product and I would immediately switch if they offered S3 protocol. The difference between SFTP and S3 is just night and day.