is an e-book format created for Amazon’s Kindle8. This format supports the CSS3 pop-up text system and HTML5 as well as built-in fonts; moreover, it possesses powerful document-formatting capabilities. It contains a function of independently activated DRM protection. AZW3 books can be created with KindleGen, a free software program from Amazon.
was developed for the first mass-produced e-book reader – Rocket eBook. The format is written in Ruby. RB files are containers holding the entire content for a Rocket eBook device. It has DRM protection capability which is not used in the books published at present due to the format’s lack of popularity.