A 64b file extension is related to emulators of Commodore C64, an 8-bit computer from the 1980's. A 64b file contains data.
64B file extension - Commodore C64 emulator data
What is 64b file? How to open 64b files?
File type specification:
The 64b file extension is associated with some emulators of Commodore C64 (Commodore 64), an 8-bit computer based on MOS platform popular in the 1980s.
The 64b file stores various data used by C64 emulators.
This 64b 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.