When do the up and down arrows appear and what are their function?

When do the up and down arrows appear and what are their function? I cannot find the documentation on these for the latest rev. I think it is related to History, though sometimes it doesn't have where I recently was reading.

The up/down arrows allow you

The up/down arrows allow you to easily iterate through a group of scriptures. For example, if you perform a search and then navigate to one of the search results, you can use the up/down arrows to easily navigate to the other search results without needing to constantly keep going back to the search screen and pick the next search result each time.

The up/down arrows also work to iterate through all of your notes (accessed from the ... button on the home screen and then select a verse from the Notes tab and then tap on up/down to iterate through them), verses that are assigned to a tag (again accessed from ... and then Tags), highlighted verses (... and then Highlights), and verses assigned to a bookmark group (accessed from the Bookmark view and then selecting any verse).