Rclone will delete partially downloaded files if it exits properly. Not if you just kill it though.
Rclone could add an atexit handler to do that...
I'd quite like to address this in a different way though - download to a temporary file name then rename the file to be the actual file at the end
This would have several advantages
- it wouldn't overwrite an existing file until the new file was complete
- partial transfers that rclone didn't clean up would be easy to spot
Rclone should probably do this for all backends capable of a partial transfer, eg local, sftp and ftp.