A hpn file extension is related to the Harpoon Classic and used for its game data files.
HPN file extension - Harpoon Classic game data
What is hpn file? How to open hpn files?
File type specification:
The hpn file extension is associated with the Harpoon Classic (also known as Larry Bond's Harpoon), a naval warfare simulation computer game for Microsoft Windows.
The hpn file contains some kind of game data.
This hpn 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.