This feature allow a user to store the files used by different field (Image, Video, Document) to be stored on a remote storage engine like AWS S3 or others.

As described here: https://confluence.ez.no/display/PR/n01+Basic+Edit+via+tree+navigation+-+explanations+-+fields+editing#n01BasicEditviatreenavigation-explanations-fieldsediting-File
The File field type AKA Asset object would then manage meta information and variations locally but keep the original file external.

Protocol:
I guess following the S3 REST API standard would be enough as a start.
(it is used by other solutions)

Benefits:
Reduce the footprint of the local installation.
could potentially help to achieve cluster setup.