Open eBook
| Filename extension | 
.opf | 
|---|---|
| Internet media type | 
application/oebps-package+xml | 
| Developed by | Open eBook Forum | 
| Initial release | 1999 | 
| Latest release | Open eBook Publication Structure (OEBPS) 2.0 September 2007 | 
| Type of format | e-Book file format | 
| Contained by | OEB Package Format (ZIP) | 
| Extended from | XML, defined subset of XHTML, CSS, Dublin Core | 
| Extended to | EPUB electronic publication standard | 
| Website | idpf.org | 
Open eBook (OEB), or formally, the Open eBook Publication Structure (OEBPS), is a legacy e-book format which has been superseded by the EPUB format. It was "based primarily on technology developed by SoftBook Press" and on XML. OEB was released with a free version belonging to public domain and a full version to be used with or without DRM by the publishing industry.
Open eBook is a ZIP file plus a Manifest file. Inside the package a defined subset of XHTML may be used, along with CSS and Dublin Core metadata. The default file extension is .opf (OEB Package Format).