Convert OPF to TCR

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 TCR file extension stands for Text Compressed for Readability, originally used by Psion Series 3 palmtop devices in the early 1990s. It stores eBooks in a proprietary format that offers better compression than PalmDOC, making it suitable for the limited storage of handheld devices. Despite the discontinuation of Psion devices, TCR files can still be read using modern eReaders like Sumatra PDF.