This is a unique feature that allows searching across the I Ching. Each internal hyperlink is the heading of a page in the Book of Changes. When more than one page in a has the same link name (Heading) it will presented as a choice.
Double-click to edit this paragraph. See what happens when you create a link for a page named 'Hexagram for Return'.
Now see what happens when you create a link for a page for hexagram 65. You are prompted to create it.
man pages
Here we consider when, where and how to make new pages. Pages and links go together. You can make either one first. One without the other leaves a site feeling unfinished which isn't a huge problem.