Files with xmdf file extension can be found as digital publications and e-books in the ever-eXtending Mobile Document Format. Used in Japan.
XMDF file extension - XMDF e-book
What is xmdf file? How to open xmdf files?
File type specification:
The xmdf file extension is related to some older ebooks in ever-eXtending Mobile Document Format that was used for digital publications around the year 1999 for the Zaurus platform (family of PDAs), developed by Sharp. Mostly used in Japan.
This xmdf file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.