OEB files exist as 2 different types. Please find information about each of them below.
Type 1: Open eBook File
Open eBook (OEB) is a legacy e-book format. It has been superseded by the EPUB format. OEB was based on technology by SoftBook Press. It was also based on XML. OEB had a free public domain version. It...
Open eBook (OEB) is a legacy e-book format. It has been superseded by the EPUB format. OEB was based on technology by SoftBook Press. It was also based on XML. OEB had a free public domain version. It also had a full version for the publishing industry to use with or without DRM. An OEB file is a ZIP file plus a Manifest file. A defined subset of XHTML may be used inside the package. CSS and Dublin Core metadata may also be used. The default file extension is .opf.
OEBPS 1.2 was released in September 2007. It was superseded by EPUB and OPS 2.0. EPUB now supersedes the OEBPS format. As the primary use of OEB files is for eBooks, many eBook readers can handle this format. For instance, Calibre allows you to open, read and manage OEB files. It can also convert them into formats like PDF, MOBI and EPUB.
There may be situations where conversion of an OEB file is necessary. This would be for ease of use or compatibility. OEB files were used primarily as a mid-state format. Publication to end-users was managed by publishers. They provided ebooks suitable for different ebook viewers. EPUB, the successor to OEB, is more likely to reach end-users as a final-state format. It also serves as a middle-state format.
Adobe Digital Editions
Calibre
Outlook Express Backup Wizard