Explain orderings in the schema. It's not clear.

[surjithctly]

In the docs, it says:

// Optional: The plugin also exports a set of 'orderings' for use in other Document Lists
  orderings: [orderRankOrdering],

But what does this code actually do? What if I did not add this? Please clarify this option as it's not understandable.

[SimeonGriggs]

Fair point, have added a link to https://www.sanity.io/docs/sort-orders above that line.