+
+The rest of the members in an SPV file's Zip archive fall into two
+categories: structure and details. ``Structure'' member names begin
+with @file{outputViewer@var{nnnnnnnnnn}}, where each @var{n} is a
+decimal digit, and end with @file{.xml}, and often include the string
+@file{_heading} in between. Each of these members represents some
+kind of output item (a table, a heading, a block of text, etc.) or a
+group of them. The member whose output goes at the beginning of the
+document is numbered 0, the next member in the output is numbered 1,
+and so on.
+
+Structure members contain XML. This XML is sometimes self-contained,
+but it often references other members in the Zip archive named as
+follows:
+
+@table @asis
+@item @file{@var{prefix}_table.xml} and @file{@var{prefix}_tableData.bin}
+@itemx @file{@var{prefix}_lightTableData.bin}
+The structure of a table plus its data. Older SPV files pair a
+@file{@var{prefix}_table.xml} file that describes the table's
+structure with a binary @file{@var{prefix}_tableData.bin} file that
+gives its data. Newer SPV files (the majority of those in the corpus)
+instead include a single @file{@var{prefix}_lightTableData.bin} file
+that incorporates both into a single binary format.
+
+@item @file{@var{prefix}_warning.xml} and @file{@var{prefix}_warningData.bin}
+@itemx @file{@var{prefix}_lightWarningData.bin}
+Same format used for tables, with a different name.
+
+@item @file{@var{prefix}_notes.xml} and @file{@var{prefix}_notesData.bin}
+@itemx @file{@var{prefix}_lightNotesData.bin}
+Same format used for tables, with a different name.
+
+@item @file{@var{prefix}_chartData.bin} and @file{@var{prefix}_chart.xml}
+The structure of a chart plus its data. Charts do not have a
+``light'' format.
+
+@item @var{prefix}_model.scf
+@itemx @var{prefix}_pmml.scf
+Not yet investigated. The corpus contains only one example of each.
+
+@itemx @var{prefix}_stats.xml
+Not yet investigated. The corpus contains few examples.
+@end table
+
+The @file{@var{prefix}} in the names of the detail members is
+typically an 11-digit decimal number that increases for each item,
+tending to skip values. Older SPV files use different naming
+conventions. Structure member refer to detail members by name, and so
+their exact names do not appear to matter as long as they are unique.
+
+@node SPV Structure Member Format
+@subsection Structure Member Format
+
+Structure members XML files claim conformance with a collection of XML
+Schemas. These schemas are distributed, under a nonfree license, with
+SPSS binaries. Fortunately, the schemas are not necessary to
+understand the structure members. To a degree, the schemas can even
+be deceptive because they document elements and attributes that are
+not in the corpus and lack documentation of elements and attributes
+that are commonly found in the corpus.
+
+Structure members use a different XML namespace for each schema, but
+these namespaces are not entirely consistent: in some SPV files, for
+example, the @code{viewer-tree} schema is associated with namespace
+@indicateurl{http://xml.spss.com/spss/viewer-tree} and in other with
+@indicateurl{http://xml.spss.com/spss/viewer/viewer-tree} (note the
+additional @file{viewer/} directory. In any case, the schema URIs are
+not resolvable to obtain the schemas themselves.
+
+One may ignore all of the above in interpreting a structure member.
+The actual XML has a simple and straightforward form that does not
+require a reader to take schemas or namespaces into account.
+
+@table @code
+@item heading
+Parent: Document root or @code{heading} @*
+Contents: [@code{pageSetup}] @code{label} [@code{container} | @code{heading}]*
+
+The root of a structure member is a @code{heading}, which represents a
+section of output beginning with a title (the @code{label}) and
+ordinarily followed by content containers or further nested
+(sub)-sections of output.
+
+The document root heading may also contain a @code{pageSetup} element.
+
+The following attributes have been observed on both document root and
+nested @code{heading} elements:
+
+@table @asis
+@item Optional attribute: @code{creator-version}
+The version of the software that created this SPV file. A string of
+the form @code{xxyyzzww} represents software version xx.yy.zz.ww,
+e.g.@: @code{21000001} is version 21.0.0.1. Trailing pairs of zeros
+are sometimes omitted, so that @code{21}, @code{210000}, and
+@code{21000000} are all version 21.0.0.0 (and the corpus contains all
+three of those forms).
+@end table
+
+The following attributes have been observed on document root
+@code{heading} elements only:
+
+@table @asis
+@item Optional attribute: @code{creator}
+The directory of the software that created this SPV file,
+e.g. @file{C:\PROGRA~1\IBM\SPSS\STATIS~1\22} or
+@file{/Applications/IBM/SPSS/Statistics/22/SPSSStatistics.app/Contents/Resources/Java/../../bin}.
+
+@item Optional attribute: @code{creation-date-time}
+The date and time at which the SPV file was written, in a
+locale-specific format, e.g. @code{Friday, May 16, 2014 6:47:37 PM
+PDT} or @code{lunedì 17 marzo 2014 3.15.48 CET} or even @code{Friday,
+December 5, 2014 5:00:19 o'clock PM EST}.
+
+@item Optional attribute: @code{lockReader}
+Whether a reader should be allowed to edit the output. The possible
+values are @code{true} and @code{false}, but the corpus only contains
+@code{false}.
+
+@item Optional attribute: @code{schemaLocation}
+This is actually an XML Namespace attribute. A reader may ignore it.
+@end table
+
+The following attributes have been observed only on nested
+@code{heading} elements:
+
+@table @asis
+@item Required attribute: @code{commandName}
+The locale-invariant name of the command that produced the output,
+e.g.@: @code{Frequencies}, @code{T-Test}, @code{Non Par Corr}.
+
+@item Optional attribute: @code{visibility}
+To what degree the output represented by the element is visible. The
+only observed value is @code{collapsed}.
+
+@item Optional attribute: @code{locale}
+The locale used for output, in Windows format, which is similar to the
+format used in Unix with the underscore replaced by a hyphen, e.g.@:
+@code{en-US}, @code{en-GB}, @code{el-GR}, @code{sr-Cryl-RS}.
+
+@item Optional attribute: @code{olang}
+The output language, e.g.@: @code{en}, @code{it}, @code{es},
+@code{de}, @code{pt-BR}.
+@end table
+
+@item label
+Parent: @code{heading} or @code{container} @*
+Contents: text
+
+Every @code{heading} and @code{container} holds a @code{label} as its
+first child. The root @code{heading} in a structure member always
+contains the string ``Output''. Otherwise, the text in @code{label}
+describes what it labels, often by naming the statistical procedure
+that was executed, e.g.@: ``Frequencies'' or ``T-Test''. Labels are
+often very generic, especially within a @code{container}, e.g.@:
+``Title'' or ``Warnings'' or ``Notes''. Label text is localized
+according to the output language, e.g. in Italian a frequency table
+procedure is labeled ``Frequenze''.
+
+The corpus contains one example of an empty label, one that contains
+no text.
+
+@item container
+Parent: @code{heading} @*
+Contents: @code{label} [@code{table} | @code{text}]
+
+A @code{container} serves to label a @code{table} or a @code{text}
+item.
+
+@table @asis
+@item Required attribute: @code{visibility}
+Either @code{visible} or @code{hidden}, this indicates whether the
+container's content is displayed.
+
+@item Optional attribute: @code{text-align}
+Presumably indicates the alignment of text within the container. The
+only observed value is @code{left}. Observed with nested @code{table}
+and @code{text} elements.
+
+@item Optional attribute: @code{width}
+The width of the container in the form @code{@var{n}px}, e.g.@:
+@code{1097px}.
+@end table
+
+@item text
+Parent: @code{container} @*
+Contents: @code{html}
+
+This @code{text} element is nested inside a @code{container}. There
+is a different @code{text} element that is nested inside a
+@code{pageParagraph}.
+
+@table @asis
+@item Required attribute: @code{type}
+One of @code{title}, @code{log}, or @code{text}.
+
+@item Optional attribute: @code{commandName}
+As on the @code{heading} element. For output not specific to a
+command, this is simply @code{log}. The corpus contains one example
+of where @code{commandName} is present but set to the empty string.
+
+@item Optional attribute: @code{creator-version}
+As on the @code{heading} element.
+@end table
+
+@item html
+Parent: @code{text} @*
+Contents: cdata
+
+The cdata contains an HTML document. In some cases, the document
+starts with @code{<html>} and ends with @code{</html}; in others the
+@code{html} element is implied. Generally the HTML includes a
+@code{head} element with a CSS stylesheet. The HTML body often begins
+with @code{<BR>}. The actual content ranges from trivial to simple:
+just discarding the CSS and tags yields readable results.
+
+@table @asis
+@item Required attribute: @code{lang}
+This always contains @code{en} in the corpus.
+@end table
+
+@item table
+Parent: @code{container} @*
+Contents: @code{tableStructure}
+
+@table @asis
+@item Required attribute: @code{commandName}
+As on the @code{heading} element.
+
+@item Required attribute: @code{type}
+One of @code{table}, @code{note}, or @code{warning}.
+
+@item Required attribute: @code{subType}
+The locale-invariant name for the particular kind of output that this
+table represents in the procedure. This can be the same as
+@code{commandName} e.g.@: @code{Frequencies}, or different, e.g.@:
+@code{Case Processing Summary}. Generic subtypes @code{Notes} and
+@code{Warnings} are often used.
+
+@item Required attribute: @code{tableId}
+A number that uniquely identifies the table within the SPV file,
+typically a large negative number such as @code{-4147135649387905023}.
+
+@item Optional attribute: @code{creator-version}
+As on the @code{heading} element. In the corpus, this is only present
+for version 21 and up and always includes all 8 digits.
+@end table
+
+@item tableStructure
+Parent: @code{table}
+Contents: @code{dataPath}
+
+@item dataPath
+Parent: @code{tableStructure}
+Contents: text
+
+Contains the name of the Zip member that holds the table details,
+e.g.@: @code{0000000001437_lightTableData.bin}.
+
+@item pageSetup
+Parent: @code{heading} @*
+Contents: @code{pageHeader} @code{pageFooter}
+
+@table @asis
+@item Required attribute: @code{initial-page-number}
+Always @code{1}.
+
+@item Optional attribute: @code{chart-size}
+Always @code{as-is} or a localization (!) of it (e.g.@: @code{dimensione
+attuale}, @code{Wie vorgegeben}).
+
+@item Optional attribute: @code{margin-left}
+@itemx Optional attribute: @code{margin-right}
+@itemx Optional attribute: @code{margin-top}
+@itemx Optional attribute: @code{margin-bottom}
+Margin sizes in the form @code{@var{size}in}, e.g.@: @code{0.25in}.
+
+@item Optional attribute: @code{paper-height}
+@itemx Optional attribute: @code{paper-width}
+Paper sizes in the form @code{@var{size}in}, e.g.@: @code{8.5in} by
+@code{11in} for letter paper or @code{8.267in} by @code{11.692in} for
+A4 paper.
+
+@item Optional attribute: @code{reference-orientation}
+Always @code{0deg}.
+
+@item Optional attribute: @code{space-after}
+Always @code{12pt}.
+@end table
+
+@item pageHeader
+@itemx pageFooter
+Parent: @code{pageSetup} @*
+Contents: @code{pageParagraph}*
+
+No attributes.
+
+@item pageParagraph
+Parent: @code{pageHeader} or @code{pageFooter} @*
+Contents: @code{text}
+
+Text to go at the top or bottom of a page, respectively.
+
+@item text
+Parent: @code{pageParagraph} @*
+Contents: [cdata]
+
+This @code{text} element is nested inside a @code{pageParagraph}. There
+is a different @code{text} element that is nested inside a
+@code{container}.
+
+The element is either empty, or contains cdata that holds almost-XHTML
+text: in the corpus, either an @code{html} or @code{p} element. It is
+@emph{almost}-XHTML because the @code{html} element designates the
+default namespace as
+@code{http://xml.spss.com/spss/viewer/viewer-tree} instead of an XHTML
+namespace.
+
+The cdata can contain substitution variables: @code{&[Page]} for the
+page number and @code{&[PageTitle]} for the page title.
+
+Typical contents (indented for clarity):
+
+@example
+<html xmlns="http://xml.spss.com/spss/viewer/viewer-tree">
+ <head></head>
+ <body>
+ <p style="text-align:right; margin-top: 0">Page &[Page]</p>
+ </body>
+</html>
+@end example
+
+@table @asis
+@item Required attribute: @code{type}
+Always @code{text}.
+@end table
+@end table
+
+@node SPV Light Detail Member Format
+@subsection Light Detail Member Format
+
+A ``light'' detail member @file{.bin} consists of a number of sections
+concatenated together, terminated by a byte 01:
+
+@example
+light-member := header title styles dimensions data 01
+@end example
+
+The first section is a 0x27-byte header:
+
+@example
+header := 01 00 version 01 (00 | 01) byte*21 00 00 table-id byte*4
+version := i1 | i3
+table-id := int
+@end example
+
+@code{header} includes @code{version}, a version number that affects
+the interpretation of some of the other data in the member. We will
+refer to ``version 1'' and ``version 3'' members later on. It also
+@code{table-id} is a binary version of @code{tableId} attribute in the
+structure member that refers to the detail member. For example, if
+@code{tableId} is @code{-4154297861994971133}, then @code{table-id}
+would be 0xdca00003. The meaning of the other variable parts of the
+header is not known.
+
+@example
+title := value 01? /* @r{localized title} */
+ value 01? 31 /* @r{subtype} */
+ value 01? 00? 58 /* @r{locale-invariant title} */
+ (31 value | 58) /* @r{caption} */
+ int[n] footnote*[n] /* @r{footnotes} */
+footnote := value (31 value | 58) byte*4
+@end example
+
+@example
+styles := 00 font*8
+ int[x1] byte*[x1]
+ int[x2] byte*[x2]
+ int[x3] byte*[x3]
+ int[x4] int*[x4]
+ string[encoding]
+ (i0 | i-1) (00 | 01) 00 (00 | 01)
+ int
+ byte[decimal] byte[grouping]
+ int[n-ccs] string*[n-ccs] /* @r{custom currency} */
+ styles2
+
+x2 := 00 00 00 01 00 00 00 00 00 00 00 00 00 02 00 00 00 00 /* @r{18 bytes} */
+
+styles2 := i0 /* @r{version 1} */
+styles2 := count(count(x5) count(x6)) /* @r{version 3} */
+x5 := byte*33 int[n] int*n
+x6 := 01 00 (03 | 04) 00 00 00
+ string[command] string[subcommand]
+ string[language] string[charset] string[locale]
+ (00 | 01) 00 (00 | 01) (00 | 01)
+ int
+ byte[decimal] byte[grouping]
+ byte*8 01
+ (string[dataset] string[datafile] i0 int i0)?
+ int[n-ccs] string*[n-ccs]
+ 2e (00 | 01) (i2000000 i0)?
+@end example
+
+In every example in the corpus, @code{x1} is 240. The meaning of the
+bytes that follow it is unknown.
+
+In every example in the corpus, @code{x2} is 18 and the bytes that
+follow it are @code{00 00 00 01 00 00 00 00 00 00 00 00 00 02 00 00 00
+00}. The meaning of these bytes is unknown.
+
+In every example in the corpus for version 1, @code{x3} is 16 and the
+bytes that follow it are @code{00 00 00 01 00 00 00 01 00 00 00 00 01
+01 01 01}. In version 3, observed @code{x3} varies from 117 to 150,
+and its bytes include a 1-byte count at offset 0x34. When the count
+is nonzero, a text string of that length at offset 0x35 is the name of
+a ``TableLook'', e.g. ``Default'' or ``Academic''.
+
+Observed values of @code{x4} vary from 0 to 17. Out of 7060 examples
+in the corpus, it is nonzero only 36 times.
+
+@code{encoding} is a character encoding, usually a Windows code page
+such as @code{en_US.windows-1252} or @code{it_IT.windows-1252}. The
+encoding string is itself encoded in US-ASCII. The rest of the
+character strings in the file use this encoding.
+
+@code{decimal} is the decimal point character. The observed values
+are @samp{.} and @samp{,}.
+
+@code{grouping} is the grouping character. The observed values are
+@samp{,}, @samp{.}, @samp{'}, @samp{ }, and zero (presumably
+indicating that digits should not be grouped).
+
+@code{n-ccs} is observed as either 0 or 5. When it is 5, the
+following strings are CCA through CCE format strings. Most commonly
+these are all @code{-,,,} but other strings occur.
+
+@example
+font := byte[index] 31 string[typeface]
+ 00 00
+ (10 | 20 | 40 | 50 | 70 | 80)[f1]
+ 41
+ (i0 | i1 | i2)[f2]
+ 00
+ (i0 | i2 | i64173)[f3]
+ (i0 | i1 | i2 | i3)[f4]
+ string[fgcolor] string[bgcolor]
+ i0 i0 00
+ (v3: int[f5] int[f6] int[f7] int[f8])
+@end example
+
+Each @code{font}, in order, represents the font style for a different
+element: title, caption, footnote, row labels, column labels, corner
+labels, data, and layers.
+
+@code{index} is the 1-based index of the @code{font}, i.e. 1 for the
+first @code{font}, through 8 for the final @code{font}.
+
+@code{typeface} is the string name of the font. In the corpus, this
+is @code{SansSerif} in over 99% of instances and @code{Times New
+Roman} in the rest.
+
+@code{fgcolor} and @code{bgcolor} are the foreground color and
+background color, respectively. In the corpus, these are always
+@code{#000000} and @code{#ffffff}, respectively.
+
+The meaning of the remaining data is unknown. It seems likely to
+include font sizes, horizontal and vertical alignment, attributes such
+as bold or italic, and margins. @code{f1} is @code{40} most of the
+time. @code{f2} is @code{i1} most of the time for the title and
+@code{i0} most of the time for other fonts.
+
+The table below lists the values observed in the corpus. When a cell
+contains a single value, then 99+% of the corpus contains that value.
+When a cell contains a pair of values, then the first value is seen in
+about two-third of the corpus and the second value in about the
+remaining one-third. In fonts that include multiple pairs, values are
+correlated, that is, for font 3, f5 = 24, f6 = 24, f7 = 2 appears
+about two-thirds of the time, as does the combination of f4 = 0, f6 =
+10 for font 7.
+
+@example
+font f1 f2 f3 f4 f5 f6 f7 f8
+
+ 1 40 1 0 0 8 10/11 1 8
+ 2 40 0 2 1 8 10/11 1 1
+ 3 40 0 2 1 24/11 24/ 8 2/3 4
+ 4 40 0 2 3 8 10/11 1 1
+ 5 40 0 0 1 8 10/11 1 4
+ 6 40 0 2 1 8 10/11 1 4
+ 7 40 0 64173 0/1 8 10/11 1 1
+ 8 40 0 2 3 8 10/11 1 4
+@end example
+
+@example
+dimensions := int[n-dims] dimension*[n-dims]
+dimension := value[name]
+ byte[d1]
+ (00 | 01 | 02)[d2]
+ (i0 | i2)[d3]
+ (00 | 01)[d4]
+ (00 | 01)[d5]
+ 01
+ int[d6]
+ int[n-categories] category*[n-categories]
+@end example
+
+@code{name} is the name of the dimension, e.g. @code{Variables},
+@code{Statistics}, or a variable name.
+
+@code{d1} is usually 0 but many other values have been observed.
+
+@code{d3} is 2 over 99% of the time.
+
+@code{d5} is 0 over 99% of the time.
+
+@code{d6} is either -1 or the 0-based index of the dimension, e.g.@: 0
+for the first dimension, 1 for the second, and so on. The latter is
+the case 98% of the time in the corpus.
+
+@example
+category := value[name] (terminal | group)
+terminal-category := 00 00 00 i2 int[index] i0
+@end example
+
+@code{name} is the name of the category (or group).
+
+@code{category} can represent a terminal category. In that case,
+@code{index} is a nonnegative integer less than @code{n-categories} in
+the @code{dimension} in which the @code{category} is nested (directly
+or indirectly).
+
+Alternatively, @code{category} can represent a @code{group} of nested
+categories:
+
+@example
+group := (00 | 01)[merge] 00 01 (i0 | i2)[data]
+ i-1 int[n-subcategories] category*[n-subcategories]
+@end example
+
+Ordinarily a group has some nested content, so that
+@code{n-subcategories} is positive, but a few instances of groups with
+@code{n-subcategories} 0 has been observed.
+
+If @code{merge} is 00, the most common value, then the group is really
+a distinct group that should be represented as such in the visual
+representation and user interface. If @code{merge} is 01, however,
+the categories in this group should be shown and treated as if they
+were direct children of the group's parent group (or if it has no
+parent group, then direct children of the dimension), and this group's
+name is irrelevant and should not be displayed. (Merged groups can be
+nested!)
+
+@code{data} appears to be i2 when all of the categories within a group
+are terminal categories that directly represent data values for a
+variable (e.g. in a frequency table or crosstabulation, a group of
+values in a variable being tabulated) and i0 otherwise, but this might
+be naive.
+
+@example
+data := int[layers] int[rows] int[columns] int*[n-dimensions]
+ int[n-data] datum*[n-data]
+@end example
+
+The values of @code{layers}, @code{rows}, and @code{columns} each
+specifies the number of dimensions represented in layers or rows or
+columns, respectively, and their values sum to the number of
+dimensions.
+
+The @code{n-dimensions} integers are a permutation of the 0-based
+dimension numbers. The first @code{layers} of them specify each of
+the dimensions represented by layers, the next @code{rows} of them
+specify the dimensions represented by rows, and the final
+@code{columns} of them specify the dimensions represented by columns.
+When there is more than one dimension of a given kind, the inner
+dimensions are given first.
+
+@example
+datum := int64[index] 00? value /* @r{version 1} */
+datum := int64[index] value /* @r{version 3} */
+@end example
+
+The format of a datum varies slightly from version 1 to version 3: in
+version 1 it allows for an extra optional 00 byte.
+
+A datum consists of an index and a value. Suppose there are @math{d}
+dimensions and dimension @math{i} for @math{0 \le i < d} has
+@math{n_i} categories. Consider the datum at coordinates @math{x_i}
+for @math{0 \le i < d}; note that @math{0 \le x_i < n_i}. Then the
+index is calculated by the following algorithm:
+
+@display
+let index = 0
+for each @math{i} from 0 to @math{d - 1}:
+ index = @math{n_i \times} index + @math{x_i}
+@end display
+
+For example, suppose there are 3 dimensions with 3, 4, and 5
+categories, respectively. The datum at coordinates (1, 2, 3) has
+index @math{5 \times (4 \times (3 \times 0 + 1) + 2) + 3 = 33}.
+
+@example
+value := 00? 00? 00? 00? raw-value
+raw-value := 01 opt-value int32[format] double[x]
+ | 02 opt-value int32[format] double[x]
+ string[varname] string[vallab] (01 | 02 | 03)
+ | 03 string[local] opt-value string[id] string[c] (00 | 01)[type]
+ | 04 opt-value int32[format] string[vallab] string[varname]
+ (01 | 02 | 03) string[vallab]
+ | 05 opt-value string[varname] string[varlabel] (01 | 02 | 03)
+ | opt-value string[format] int32[n-substs] substitution*[n-substs]
+substitution := i0 value
+ | int32[x] value*[x + 1] /* @r{x > 0} */
+opt-value := 31 i0 (i0 | i1 string) opt-value-i0-v1 /* @r{version 1} */
+ | 31 i0 (i0 | i1 string) opt-value-i0-v3 /* @r{version 3} */
+ | 31 i1 int32[footnote-number] nested-string
+ | 31 i2 (00 | 01 | 02) 00 (i1 | i2 | i3) nested-string
+ | 31 i3 00 00 01 00 i2 nested-string
+ | 58
+opt-value-i0-v1 := 00 (i1 | i2) 00 00 int32 00 00
+opt-value-i0-v3 := count(counted-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
+nested-string := 00 00 count(counted-string (58 | 31 style) 58)
+counted-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 that originates from the software program (rather than
+from user data). The string is provided in two forms: @code{c} is in
+English and @code{local} is localized to the user's language
+environment. In an English-language locale, the two strings are often
+the same, and in cases where they differ @code{c} is often abbreviated
+or obscure and @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{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.
+
+@item 04
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