+@node SPV Legacy Member Data
+@subsection Data
+
+@cartouche
+@format
+Data @result{} NumericData*[@t{n-variables}] StringData?
+NumericData @result{} byte*288[@t{variable-name}] double*[@t{n-data}]
+@end format
+@end cartouche
+
+Data follow the Metadata in the legacy binary format, with sources in
+the same order. Each NumericSeries begins with a @code{variable-name}
+that generally indicates its role in the pivot table, e.g.@: ``cell'',
+``cellFormat'', ``dimension0categories'', ``dimension0group0'',
+followed by the numeric data, one double per datum. A double with the
+maximum negative double @code{-DBL_MAX} represents the system-missing
+value SYSMIS.
+
+@cartouche
+@format
+StringData @result{} i1 string[@t{source-name}] Pairs Labels
+
+Pairs @result{} int[@t{n-string-vars}] PairSeries*[@t{n-string-vars}]
+PairVar @result{} string[@t{pair-var-name}] int[@t{n-pairs}] Pair*[@t{n-pairs}]
+Pair @result{} int[@t{i}] int[@t{j}]
+
+Labels @result{} int[@t{n-labels}] Label*[@t{n-labels}]
+Label @result{} int[@t{frequency}] int[@t{s}]
+@end format
+@end cartouche
+
+A source may include a mix of numeric and string data values. When a
+source includes any string data, the data values that are strings are
+set to SYSMIS in the NumericData, and StringData follows the
+NumericData. A source that contains no string data omits the
+StringData. To reliably determine whether a source includes
+StringData, the reader should check whether the offset following the
+NumericData is the offset of the next source, as indicated by its
+Metadata (or the end of the member, in the case of the last source).
+
+StringData repeats the name of the source (from Metadata).
+
+The string data overlays the numeric data. @code{n-string-vars} is
+the number of variables in the source that include string data. More
+precisely, it is the 1-based index of the last variable in the source
+that includes any string data; thus, it would be 4 if there are 5
+variables and only the fourth one includes string data.
+
+Each PairVar consists a sequence of 0 or more Pair nonterminals, each
+of which maps from a 0-based index within variable @code{i} to a
+0-based label index @code{j}, e.g.@: pair @code{i} = 2, @code{j} = 3,
+means that the third data value (with value SYSMIS) is to be replaced
+by the string of the fourth Label.
+
+The labels themselves follow the pairs. The valuable part of each
+label is the string @code{s}. Each label also includes a
+@code{frequency} that reports the number of pairs that reference it
+(although this is not useful).
+
+@node SPV Legacy Detail Member XML Format
+@section Legacy Detail Member XML Format
+
+This format is still under investigation.
+
+The design of the detail XML format is not what one would end up with
+for describing pivot tables. This is because it is a special case
+of a much more general format (``visualization XML'' or ``VizML'')
+that can describe a wide range of visualizations. Most of this
+generality is overkill for tables, and so we end up with a funny
+subset of a general-purpose format.
+
+The important elements of the detail XML format are:
+
+@itemize @bullet
+@item
+Variables. Variables in detail XML roughly correspond to the
+dimensions in a light detail member. There is one variable for each
+dimension, plus one variable for each level of labeling along an axis.
+
+The bulk of variables are defined with @code{sourceVariable} elements.
+The data for these variables comes from the associated
+@code{tableData.bin} member. Some variables are defined, with
+@code{derivedVariable} elements, as a constant or in terms of a
+mapping function from a source variable.
+
+@item
+Assignment of variables to axes. A variable can appear as columns, or
+rows, or layers. The @code{faceting} element and its sub-elements
+describe this assignment.
+@end itemize
+
+All elements have an optional @code{id} attribute. In practice many
+elements are assigned @code{id} attributes that are never referenced.
+
+@menu
+* SPV Detail visualization Element::
+* SPV Detail userSource Element::
+* SPV Detail sourceVariable Element::
+* SPV Detail derivedVariable Element::
+* SPV Detail extension Element::
+* SPV Detail graph Element::
+* SPV Detail location Element::
+* SPV Detail coordinates Element::
+* SPV Detail faceting Element::
+* SPV Detail facetLayout Element::
+@end menu
+
+@node SPV Detail visualization Element
+@subsection The @code{visualization} Element
+
+@format
+Parent: Document root
+Contents:
+ extension?
+ userSource
+ (sourceVariable @math{|} derivedVariable)@math{+}
+ graph
+ labelFrame@math{+}
+ container?
+ style@math{+}
+ layerController?
+@end format
+
+This element has the following attributes.
+
+@defvr {Required} creator
+The version of the software that created this SPV file, as a string of
+the form @code{xxyyzz}, which represents software version xx.yy.zz,
+e.g.@: @code{160001} is version 16.0.1. The corpus includes major
+versions 16 through 19.
+@end defvr
+
+@defvr {Required} date
+The date on the which the file was created, as a string of the form
+@code{YYYY-MM-DD}.
+@end defvr
+
+@defvr {Required} lang
+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}.
+@end defvr
+
+@defvr {Required} name
+The title of the pivot table, localized to the output language.
+@end defvr
+
+@defvr {Required} style
+The @code{id} of a @code{style} element (@pxref{SPV Detail style
+element}). This is the base style for the entire pivot table. In
+every example in the corpus, the value is @code{visualizationStyle}
+and the corresponding @code{style} element has no attributes other
+than @code{id}.
+@end defvr
+
+@defvr {Required} type
+A floating-point number. The meaning is unknown.
+@end defvr
+
+@defvr {Required} version
+The visualization schema version number. In the corpus, the value is
+one of 2.4, 2.5, 2.7, and 2.8.
+@end defvr
+
+@node SPV Detail userSource Element
+@subsection The @code{userSource} Element
+
+Parent: @code{visualization} @*
+Contents:
+
+This element has the following attributes.
+
+@defvr {Optional} missing
+Always @code{listwise}.
+@end defvr
+
+@node SPV Detail sourceVariable Element
+@subsection The @code{sourceVariable} Element
+
+Parent: @code{visualization} @*
+Contents: @code{extension}* (@code{format} @math{|} @code{stringFormat})?
+
+This element defines a variable whose values can be used elsewhere in
+the visualization. It ties this element's @code{id} to a variable
+from the @file{tableData.bin} member that corresponds to this
+@file{.xml}.
+
+This element has the following attributes.
+
+@defvr {Required} categorical
+Always set to @code{true}.
+@end defvr
+
+@defvr {Required} source
+Always set to @code{tableData}, the @code{source-name} in the
+corresponding @file{tableData.bin} member (@pxref{SPV Legacy Member
+Metadata}).
+@end defvr
+
+@defvr {Required} sourceName
+The name of a variable within the source, the @code{variable-name} in
+the corresponding @file{tableData.bin} member (@pxref{SPV Legacy
+Member Data}).
+@end defvr
+
+@defvr {Optional} dependsOn
+The @code{variable-name} of a variable linked to this one, so that a
+viewer can work with them together. For a group variable, this is the
+name of the corresponding categorical variable.
+@end defvr
+
+@defvr {Optional} label
+The variable label, if any
+@end defvr
+
+@defvr {Optional} labelVariable
+The @code{variable-name} of a variable whose string values correspond
+one-to-one with the values of this variable and are suitable for use
+as value labels.
+@end defvr
+
+@node SPV Detail derivedVariable Element
+@subsection The @code{derivedVariable} Element
+
+Parent: @code{visualization} @*
+Contents: @code{extension}* (@code{format} @math{|} @code{stringFormat} @code{valueMapEntry}*)
+
+Like @code{sourceVariable}, this element defines a variable whose
+values can be used elsewhere in the visualization. Instead of being
+read from a data source, the variable's data are defined by a
+mathematical expression.
+
+This element has the following attributes.
+
+@defvr {Required} categorical
+Always set to @code{true}.
+@end defvr
+
+@defvr {Required} value
+An expression that defines the variable's value. In theory this could
+be an arbitrary expression in terms of constants, functions, and other
+variables, e.g.@: @math{(@var{var1} + @var{var2}) / 2}. In practice,
+the corpus contains only the following forms of expressions:
+
+@table @code
+@item constant(@var{number})
+@itemx constant(@var{variable})
+A constant. The meaning when a variable is named is unknown.
+Sometimes the ``variable name'' has spaces in it.
+
+@item map(@var{variable})
+Transforms the values in the named @var{variable} using the
+@code{valueMapEntry}s contained within the element.
+@end table
+@end defvr
+
+@defvr {Optional} dependsOn
+The @code{variable-name} of a variable linked to this one, so that a
+viewer can work with them together. For a group variable, this is the
+name of the corresponding categorical variable.
+@end defvr
+
+@menu
+* SPV Detail valueMapEntry Element::
+@end menu
+
+@node SPV Detail valueMapEntry Element
+@subsubsection The @code{valueMapEntry} Element
+
+Parent: @code{derivedVariable} @*
+Contents: empty
+
+A @code{valueMapEntry} element defines a mapping from one or more
+values of a source expression to a target value. (In the corpus, the
+source expression is always just the name of a variable.) Each target
+value requires a separate @code{valueMapEntry}. If multiple source
+values map to the same target value, they can be combined or separate.
+
+@code{valueMapEntry} has the following attributes.
+
+@defvr {Required} from
+A source value, or multiple source values separated by semicolons,
+e.g.@: @code{0} or @code{13;14;15;16}.
+@end defvr
+
+@defvr {Required} to
+The target value.
+@end defvr
+
+@node SPV Detail extension Element
+@subsection The @code{extension} Element
+
+This is a general-purpose ``extension'' element. Readers that don't
+understand a given extension should be able to safely ignore it. The
+attributes on this element, and their meanings, vary based on the
+context. Each known usage is described separately below. The current
+extensions use attributes exclusively, without any nested elements.
+
+@subsubheading @code{visualization} Parent Element
+
+With @code{visualization} as its parent element, @code{extension} has
+the following attributes.
+
+@defvr {Optional} numRows
+An integer that presumably defines the number of rows in the displayed
+pivot table.
+@end defvr
+
+@defvr {Optional} showGridline
+Always set to @code{false} in the corpus.
+@end defvr
+
+@defvr {Optional} minWidthSet
+@defvrx {Optional} maxWidthSet
+Always set to @code{true} in the corpus.
+@end defvr
+
+@subsubheading @code{container} Parent Element
+
+With @code{container} as its parent element, @code{extension} has the
+following attributes.
+
+@defvr {Required} combinedFootnotes
+Always set to @code{true} in the corpus.
+@end defvr
+
+@subsubheading @code{sourceVariable} and @code{derivedVariable} Parent Element
+
+With @code{sourceVariable} or @code{derivedVariable} as its parent
+element, @code{extension} has the following attributes. A given
+parent element often contains several @code{extension} elements that
+specify the meaning of the source data's variables or sources, e.g.@:
+
+@example
+<extension from="0" helpId="corrected_model"/>
+<extension from="3" helpId="error"/>
+<extension from="4" helpId="total_9"/>
+<extension from="5" helpId="corrected_total"/>
+@end example
+
+@defvr {Required} from
+An integer or a name like ``dimension0''.
+@end defvr
+
+@defvr {Required} helpId
+An identifier.
+@end defvr
+
+@node SPV Detail graph Element
+@subsection The @code{graph} Element
+
+Parent: @code{visualization} @*
+Contents: @code{location}@math{+} @code{coordinates} @code{faceting} @code{facetLayout} @code{interval}
+
+@code{graph} has the following attributes.
+
+@defvr {Required} cellStyle
+@defvrx {Required} style
+Each of these is the @code{id} of a @code{style} element (@pxref{SPV
+Detail style element}). The former is the default style for
+individual cells, the latter for the entire table.
+@end defvr
+
+@node SPV Detail location Element
+@subsection The @code{location} Element
+
+Parent: @code{graph} @*
+Contents: empty
+
+Each instance of this element specifies where some part of the table
+frame is located. All the examples in the corpus have four instances
+of this element, one for each of the parts @code{height},
+@code{width}, @code{left}, and @code{top}. Some examples in the
+corpus add a fifth for part @code{bottom}, even though it is not clear
+how all of @code{top}, @code{bottom}, and @code{heigth} can be honored
+at the same time. In any case, @code{location} seems to have little
+importance in representing tables; a reader can safely ignore it.
+
+@defvr {Required} part
+One of @code{height}, @code{width}, @code{top}, @code{bottom}, or
+@code{left}. Presumably @code{right} is acceptable as well but the
+corpus contains no examples.
+@end defvr
+
+@defvr {Required} method
+How the location is determined:
+
+@table @code
+@item sizeToContent
+Based on the natural size of the table. Observed only for
+parts @code{height} and @code{width}.
+
+@item attach
+Based on the location specified in @code{target}. Observed only for
+parts @code{top} and @code{bottom}.
+
+@item fixed
+Using the value in @code{value}. Observed only for parts @code{top},
+@code{bottom}, and @code{left}.
+
+@item same
+Same as the specified @code{target}. Observed only for part
+@code{left}.
+@end table
+@end defvr
+
+@defvr {Optional} min
+Minimum size. Only observed with value @code{100pt}. Only observed
+for part @code{width}.
+@end defvr
+
+@defvr {Dependent} target
+Required when @code{method} is @code{attach} or @code{same}, not
+observed otherwise. This is the ID of an element to attach to.
+Observed with the ID of @code{title}, @code{footnote}, @code{graph},
+and other elements.
+@end defvr
+
+@defvr {Dependent} value
+Required when @code{method} is @code{fixed}, not observed otherwise.
+Observed values are @code{0%}, @code{0px}, @code{1px}, and @code{3px}
+on parts @code{top} and @code{left}, and @code{100%} on part
+@code{bottom}.
+@end defvr
+
+@node SPV Detail coordinates Element
+@subsection The @code{coordinates} Element
+
+Parent: @code{graph} @*
+Contents: empty
+
+This element is always present and always empty, with no attributes
+(except @code{id}).
+
+@node SPV Detail faceting Element
+@subsection The @code{faceting} Element
+
+Parent: @code{graph} @*
+Contents: @code{cross} @code{layer}*
+
+The @code{faceting} element describes the row, column, and layer
+structure of the table. Its @code{cross} child determines the row and
+column structure, and each @code{layer} child (if any) represents a
+layer.
+
+@code{faceting} has no attributes (other than @code{id}).
+
+@subsubheading The @code{cross} Element
+
+Parent: @code{faceting} @*
+Contents: @code{nest} @code{nest}
+
+The @code{cross} element describes the row and column structure of the
+table. It has exactly two @code{nest} children, the first of which
+describes the table's rows and the second the table's columns.
+
+@code{cross} has no attributes (other than @code{id}).
+
+@subsubheading The @code{nest} Element
+
+Parent: @code{cross} @*
+Contents: @code{variableReference}@math{+}
+
+A given @code{nest} usually consists of one or more dimensions, each
+of which is represented by @code{variableReference} child elements.
+Minimally, a dimension has two @code{variableReference} children, one
+for the categories, one for the data, e.g.:
+