I have a question about rclone: I would like to know whether rclone actually uploads just the modified part of the file? when syncing it to a cloud source
The whole file.
is there anyway i could just upload the delta alone?
You can use a 3rd party binary diff tool.
Or you could use a backup program like restic (which can use rclone directly) which will do binary diffs.
Can you please provide some link reference for the same?