+@example
+value := 00? 00? 00? 00? raw-value
+raw-value :=
+ 01 value-mod int32[format] double[x]
+ | 02 value-mod int32[format] double[x]
+ string[varname] string[vallab] (01 | 02 | 03)
+ | 03 string[local] value-mod string[id] string[c] (00 | 01)[type]
+ | 04 value-mod int32[format] string[vallab] string[varname]
+ (01 | 02 | 03) string[s]
+ | 05 value-mod string[varname] string[varlabel] (01 | 02 | 03)
+ | value-mod string[format] int32[n-substs] substitution*[n-substs]
+substitution :=
+ i0 value
+ | int32[x] value*[x + 1] /* @r{x > 0} */
+value-mod :=
+ 31 i0 (i0 | i1 string[subscript]) value-mod-i0-v1 /* @r{version 1} */
+ | 31 i0 (i0 | i1 string[subscript]) value-mod-i0-v3 /* @r{version 3} */
+ | 31 i1 int32[footnote-number] template
+ | 31 i2 (00 | 01 | 02) 00 (i1 | i2 | i3) template
+ | 31 i3 00 00 01 00 i2 template
+ | 58
+value-mod-i0-v1 := 00 (i1 | i2) 00 00 int32 00 00
+value-mod-i0-v3 := count(template-string
+ (58 | 31 style)
+ (58
+ | 31 i0 i0 i0 i0 01 00 (01 | 02 | 08)
+ 00 08 00 0a 00))
+
+style := 01? 00? 00? 00? 01 string[fgcolor] string[bgcolor] string[font] byte
+template := 00 00 count(template-string (58 | 31 style) 58)
+template-string := count((i0 (58 | 31 string))?)
+@end example
+
+A @code{value} boils down to a number or a string. There are several
+possibilities, which one can distinguish by the first nonzero byte in
+the encoding:
+
+@table @code
+@item 01
+The numeric value @code{x}, presented to the user formatted according
+to @code{format}, which is in the format described for system files.
+@xref{System File Output Formats}, for details. Most commonly
+@code{format} has width 40 (the maximum).
+
+An @code{x} with the maximum negative double @code{-DBL_MAX}
+represents the system-missing value SYSMIS. (HIGHEST and LOWEST have
+not been observed.) @xref{System File Format}, for more about these
+special values.
+
+@item 02
+Similar to @code{01}, with the additional information that @code{x} is
+a value of variable @code{varname} and has value label @code{vallab}.
+Both @code{varname} and @code{vallab} can be the empty string, the
+latter very commonly.
+
+The meaning of the final byte is unknown. Possibly it is connected to
+whether the value or the label should be displayed.
+
+@item 03
+A text string, in two forms: @code{c} is in English, and sometimes
+abbreviated or obscure, and @code{local} is localized to the user's
+locale. In an English-language locale, the two strings are often the
+same, and in the cases where they differ, @code{local} is more
+appropriate for a user interface, e.g.@: @code{c} of ``Not a PxP table
+for MCN...'' versus @code{local} of ``Computed only for a PxP table,
+where P must be greater than 1.''
+
+@code{c} and @code{local} are always either both empty or both
+nonempty.
+
+@code{id} is a brief identifying string whose form seems to resemble a
+programming language identifier, e.g.@: @code{cumulative_percent} or
+@code{factor_14}. It is not unique.
+
+@code{type} is 00 for text taken from user input, such as syntax
+fragment, expressions, file names, data set names, and 01 for fixed
+text strings such as names of procedures or statistics. In the former
+case, @code{id} is always the empty string; in the latter case,
+@code{id} is still sometimes empty.
+
+@item 04
+The string value @code{s}, presented to the user formatted according
+to @code{format}. The format for a string is not too interesting, and
+clearly invalid formats like A16.39 or A255.127 or A134.1 abound in
+the corpus, so readers should probably ignore the format entirely.
+
+@code{s} is a value of variable @code{varname} and has value label
+@code{vallab}. @code{varname} is never empty but @code{vallab} is
+commonly empty.
+
+The meaning of the final byte is unknown.
+
+@item 05
+Variable @code{varname}, which is rarely observed as empty in the
+corpus, with variable label @code{varlabel}, which is often empty.
+
+The meaning of the final byte is unknown.
+@end itemize