Files with pkpack file extension can be found as old compressed archives.
PKPACK file extension - Compressed archive
What is pkpack file? How to open pkpack files?
File type specification:
The pkpack file extension seems to have been used in the past for some sort of compressed archives, perhaps using early PKware software. No further information regarding this file type could be found.
This pkpack 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.