OrderedCollection is similar, but because "items" is defined as being "unordered" in the JSON-LD @'context they need to override that with a different name. So they introduce orderedItems and put an index on the page (which I have opinions about, but that's a story for another time).
We've already gone into how we have problems with the fact that next and prev can be objects, Link objects (which are different), or URIs. That isn't what I want to focus on here.
3/