Some books or periodicals from Amazon Kindle store have this cool feature that shows a breadcrumb or title bar when you read them. It shows up as the first line of the text. It is not the bar that has the battery and wireless signal icons. It is that first line underneath, right above the content.
For example, if you are in the middle of chapter 2 it shows the title of the chapter in that line. It is really cool and I would like to implement that in my books.
I have proper TOC, cover and start page. I followed the guidelines in Kindle Publishing Guide. Actually, I am using KindleGen to convert from "on-the-fly" generated EPUB. I am mentioning this to weed out simple RTFM answers. :) In all the guides I read, I have not found anything that mentioned described feature.
The books that have that feature are encrypted, so I can't find out how they work by looking at their files. Another thing, they are in AZW format, which supposed to be just MOBI renamed. Perhaps the described feature is exclusive to Kindle?
I thought I would ask the Kindle/MOBI/EPUB gurus out there: How can I implement such a feature in my own books?