Not every Preferences file is stored as an iff file of type pref.  the
palette.ilbm and pointer.ilbm files contain a regular ilbm form to store
their imagery.  The win.pat and wb.pat files use a raw format with 16
bytes reserved, followed by a WORD giving the total size of the pattern, a
WORD giving the bitplane count, and byte arrays (currently 32 bytes) for
each bitplane.  The format of the wbconfig.prefs file is private.