Files with j64 file extension can be found as ROM images for some Virtual Jaguar emulators.
J64 file extension - Virtual Jaguar ROM image
What is j64 file? How to open j64 files?
File type specification:
The J64 file extension is reported to have been occasionally used for a Virtual Jaguar ROM file in some emulator software.
Most likely some old format without support. No further information could be found.
This j64 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.