How is {index} processed in documentation?

I’m having a look at generating app documentation.

The docs above say that when you want to generate a an index you can simply do so by including {index} in your But taking at the ERPNext user manual has left me a little confused.

This index only has 17 items (image above). But The actual generated documentation has 20! (image below).

Where are the last 3 items are coming from?