diff --git a/sc2/doc/devel/pkgformat b/sc2/doc/devel/pkgformat
new file mode 100644
index 000000000..617249aaf
--- /dev/null
+++ b/sc2/doc/devel/pkgformat
@@ -0,0 +1,106 @@
+The .pkg/.ndx format as used for Starcon.pkg on the 3DO cd.
+Acquired directly from the source.
+
+Everything is stored LSB first.
+
+Main header: (resinit.c, _GetResFileData())
+position   length  meaning
+0x00       2       Whether or not the file is packaged (res_flags)
+                       (has all files in the .pkg file itself)
+                   0 - the .pkg file is not packaged
+                   else - the .pkg file is packaged
+0x02       4       offset from the beginning of the file where the list
+                       of package information is stored (packmem_list_offs)
+0x06       4       offset from the beginning of the file where the list
+                       of pathnames is stored (path_list_offs)
+0x0a       4       offset from the beginning of the file where the list
+                       of filenames is stored (file_list_offs)
+0x0e       2       number of packages in the file (num_packages)
+0x10       2       number of types of packages present in the file (num_types)
+0x12       4       length of this header. (index_info.header_len)
+                       (unused if the .pkg file is not packaged)
+0x16       8*num_packages:
+                   On position i the information for package i + 1 is
+                       stored. There is no package 0.
+           4       p.packmem_info
+                   bits 0-7: number of resource types
+                   bits 8-20: number of resource instances
+                   bits 21-31: index in file_list_offs of the file name for
+                       this resource (only for packaged files)
+           4       p.flags_and_data_loc
+                   (MSB is flags, rest is data_loc,
+                   if MSB == 0, then of the data_loc only the low 16 bits
+                       are used as a MEM_HANDLE (only in memory),
+                   if MSB == 0xff, then the data_loc is an offset in the
+                       file)
+0x16+8*num_packages  Type information
+           2*num_types
+                   t.instance_count
+                   The number of instances there are of this type.
+                   On position i the instance count for type i + 1 is
+                       stored. There's no type 0.
+packmem_list_offs (should be directly after the index info):
+                   for each of the num_packages packages:
+                     for each of the resource types for this package
+                         (as in p.packmem_info):
+           4           bits 0-7: The type number for this type. What that
+                                     number means isn't specified, and may
+                                     vary per .pkg file.
+                                 For the 3DO SC2 starcon.pkg file these are:
+                                 0 - not a type
+                                 1 - Graphics data (GFXRES)
+                                 2 - String data (STRTAB)
+                                 3 - Music data (MUSICRES)
+                                 4 - Resource index (RES_INDEX)
+                                 5 - Code (CODE)
+                       bits 8-20: The instance number of the first instance
+                                  of this type in this package. Every
+                                  following instance has a number 1 higher
+                                  than the one before.
+                       bits 21-31: number of resources of this type in the
+                                   package
+                     for each of the resource instances for this package
+                         (as in p.packmem_info):
+           2           if this is a packaged file: multiply by 4 to get
+                           the length of this package.
+                       if this is a file that is not packaged: 
+                           (the same position is in memory used as a
+                           MEM_HANDLE to the actual data)
+path_list_offs     (should be directly after the packmem list)
+           ?       null terminated path strings, indexed from the file list
+                       table
+file_list_offs     (should be directly after the path list)
+           ?       A number of file info structures. For packaged files,
+                       these are indexed from the p.packmem_info (so (at most)
+                       one per package). For non-packaged files, these are
+                       indexed from an entry for an instance from
+                       p.packmem_list (so possibly more per package)
+                   These structures are in this form:
+           13        file info:
+           2         location relative to path_list_offs of the
+                         the path to this file, or 0xffff if no path.
+           8         filename (8 chars or null-terminated)
+           3         extension (3 chars or null-terminated)
+
+
+
+Resources with type 'resource index' (type 4 in the 3DO sc2 starcon.pkg file)
+are files with the same format as this .pkg file itself.
+
+
+For music resources: (type 3 in the 3DO sc2 starcon.pkg file)
+If the first 3 characters are 'CDA', from the next character to the first
+nul char, or 3 characters after the first period (whatever comes first) is
+used as a filename with aif audio data to play. (CDA stands for CD-audio.
+The source code mentions 'red book', but it's not (red book is the standard
+for audio CD's)). The rest of the file (just a few more chars) seems to be
+garbage.
+If the first 3 characters are something else, the entire file (including the
+first 3 characters) are used as a MOD file. (As the mod file uses those char
+as the title of the song, a mod file with the title beginning with 'CDA'
+will go wrong).
+
+
+
+Initial version of this file 2002-10-10 by Serge van den Boom.
+