Apple DocViewer file
File type: Miscellaneous file
An ONPF file is associated with Apple DocViewer, a documentation viewer for older versions of Mac OS.
File type category:
Miscellaneous file
Date updated: September 27, 2026
Apple DocViewer was software from Apple for viewing documentation and related help content on older Mac OS systems. The ONPF file extension identifies data associated with that viewer.
Open an ONPF file on a compatible older Mac OS system with Apple DocViewer, if the associated documentation installation is available.
If you need the readable content in another format, use any copy or export functions available in Apple DocViewer.
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