Convert OPF to AZW3

The Open Packaging Format (OPF) is a critical component in the EPUB digital publishing standard, specifically designed for eBooks. OPF files serve as a manifest that organizes and structures the contents of an EPUB file, including metadata, the reading order, and resource files. This standard, introduced by the International Digital Publishing Forum (IDPF) in 2007, aimed to streamline the publication and distribution of eBooks, ensuring compatibility across various devices and reading software. The OPF's primary purpose is to enhance the accessibility and interoperability of digital content within the rapidly evolving landscape of electronic publishing.

The AZW3 file extension, also known as Kindle Format 8 (KF8), is a proprietary eBook format developed by Amazon. Introduced in 2011 alongside the Kindle Fire, AZW3 supports advanced formatting features such as HTML5 and CSS3, enhancing the visual presentation of eBooks. It is primarily used for Amazon Kindle devices and applications, providing a richer reading experience compared to its predecessor, AZW. The format is backward-compatible with MOBI, ensuring older Kindle devices can still access the content.