As brought up in #9(comment), users could potentially only deposit objects information depending on their tools and research subject of interest (e.g. endpoint feature extraction).
During a quick zoom discussion with @sbesson and @pcmasuzzo, it was decided this will NOT be part of the v0.1 "Tracks" specification (the Links table thus keeping its MUST requirement) but we will instead define some separate "Objects" specification in the future.
The Objects and Tracks specifications could then work on different levels with Tracks inheriting and using the Objects spec, possibly with extra requirements or restrictions.