PNF, Precompiled INF File (.pnf)
The PNF System file format
PNF files are system files that can be recognized or used by many different programs on your computer. However, they should never be opened manually by clicking on the file as simple changes within the file can have severe consequences for the instances and programs that rely on the files. These files are automatically generated by a system once an INF file is run. They are typically found in the same directory (%Windir%Inf or %Systemroot%Inf). Since the files are generated automatically, deleting them is no problem. When a PNF file in use was deleted, the system will simply generate a new one when needed.
Technical details of PNF files
Files of the PNF format are maintained by the system itself. They are configuration files that are very closely related to INF files in a way that they are basically INF files that have been precompiled. PNF files are created because they make accessing information of INF files easier for certain programs. The content of a PNF often includes the file name and location of the INF file it was created from, as well as other data.