It is my understanding that there is currently no way for StructuredDataOnCommons edits to be marked as minor.
There is currently friction on Wikimedia Commons, where a tool for adding Structured Data claims gets more traction and some users have their watchlist flooded with tool-assisted edits. Some users feel that these edits should be marked as minor, which could make them easier to filter out in the watchlist.
There is not necessarily consensus that these particular tool-assisted edits should always be marked as minor, or that they should be mark-able as minor. However, this is a conversation that the community cannot really have, since there would be no technical way to implement it at the moment.
(Also, the particular problem described above could arguably be better addressed with T174349: Allow tag filter on Special:RecentChanges and Watchlist to be inverted (enable the not operator) ; but nevertheless the general point has merits and has wider application than just the particular tool being discuss)
As this is done (if I’m not mistaken) via wbsetclaim, this somewhat relates to T52933: api module wbsetclaim doesn't accept the bot param.
(Feel free to rename this task to be more general, as I suppose it’s not about Commons in particular)
(I would have thought there was already a task for this, but could not find any − please merge if I missed it)