+
+@defvr {Attribute} errorCharacter
+A character that replaces the formatted value when it cannot otherwise
+be represented in the given format. Always @samp{*}.
+@end defvr
+
+@subsubheading Date and Time Attributes
+
+These attributes are used with @code{dateTime} and @code{elapsedTime}
+formats or both.
+
+@defvr {Attribute} separatorChars
+Exactly four characters. In order, these are used for: decimal point,
+grouping, date separator, time separator. Always @samp{.,-:}.
+@end defvr
+
+@defvr {Attribute} mdyOrder
+Within a date, the order of the days, months, and years.
+@code{dayMonthYear} is the only observed value, but one would expect
+that @code{monthDayYear} and @code{yearMonthDay} to be reasonable as
+well.
+@end defvr
+
+@defvr {Attribute} showYear
+@defvrx {Attribute} yearAbbreviation
+Whether to include the year and, if so, whether the year should be
+shown abbreviated, that is, with only 2 digits. Each is @code{true}
+or @code{false}; only values of @code{true} and @code{false},
+respectively, have been observed.
+@end defvr
+
+@defvr {Attribute} showMonth
+@defvrx {Attribute} monthFormat
+Whether to include the month (@code{true} or @code{false}) and, if so,
+how to format it. @code{monthFormat} is one of the following:
+
+@table @code
+@item long
+The full name of the month, e.g.@: in an English locale,
+@code{September}.
+
+@item short
+The abbreviated name of the month, e.g.@: in an English locale,
+@code{Sep}.
+
+@item number
+The number representing the month, e.g.@: 9 for September.
+
+@item paddedNumber
+A two-digit number representing the month, e.g.@: 09 for September.
+@end table
+
+Only values of @code{true} and @code{short}, respectively, have been
+observed.
+@end defvr
+
+@defvr {Attribute} dayPadding
+@defvrx {Attribute} dayOfMonthPadding
+@defvrx {Attribute} hourPadding
+@defvrx {Attribute} minutePadding
+@defvrx {Attribute} secondPadding
+These attributes presumably control whether each field in the output
+is padded with spaces to its maximum width, but the details are not
+understood. The only observed value for any of these attributes is
+@code{true}.
+@end defvr
+
+@defvr {Attribute} showDay
+@defvrx {Attribute} showHour
+@defvrx {Attribute} showMinute
+@defvrx {Attribute} showSecond
+@defvrx {Attribute} showMillis
+These attributes presumably control whether each field is displayed
+in the output, but the details are not understood. The only
+observed value for any of these attributes is @code{true}.
+@end defvr
+
+@defvr {Attribute} dayType
+This attribute is always @code{month} in the corpus, specifying that
+the day of the month is to be displayed; a value of @code{year} is
+supposed to indicate that the day of the year, where 1 is January 1,
+is to be displayed instead.
+@end defvr
+
+@defvr {Attribute} hourFormat
+@code{hourFormat}, if present, is one of:
+
+@table @code
+@item AMPM
+The time is displayed with an @code{am} or @code{pm} suffix, e.g.@:
+@code{10:15pm}.
+
+@item AS_24
+The time is displayed in a 24-hour format, e.g.@: @code{22:15}.
+
+This is the only value observed in the corpus.
+
+@item AS_12
+The time is displayed in a 12-hour format, without distinguishing
+morning or evening, e.g.@: @code{10;15}.
+@end table
+
+@code{hourFormat} is sometimes present for @code{elapsedTime} formats,
+which is confusing since a time duration does not have a concept of AM
+or PM. This might indicate a bug in the code that generated the XML
+in the corpus, or it might indicate that @code{elapsedTime} is
+sometimes used to format a time of day.
+@end defvr
+
+@subsubheading Numeric Attributes
+
+These attributes are used for formats when @code{baseFormat} is
+@code{number}. Attributes @code{maximumFractionDigits}, and
+@code{minimumFractionDigits}, and @code{useGrouping} are also used
+when @code{baseFormat} is @code{elapsedTime}.
+
+@defvr {Attribute} minimumIntegerDigits
+Minimum number of digits to display before the decimal point. Always
+observed as @code{0}.
+@end defvr
+
+@defvr {Attribute} maximumFractionDigits
+@defvrx {Attribute} maximumFractionDigits
+Maximum or minimum, respectively, number of digits to display after
+the decimal point. The observed values of each attribute range from 0
+to 9.
+@end defvr
+
+@defvr {Attribute} useGrouping
+Whether to use the grouping character to group digits in large
+numbers. It would make sense for the grouping character to come from
+the @code{separatorChars} attribute, but that attribute is only
+present when @code{baseFormat} is @code{dateTime} or
+@code{elapsedTime}, in the corpus at least. Perhaps that is because
+this attribute has only been observed as @code{false}.
+@end defvr
+
+@defvr {Attribute} scientific
+This attribute controls when and whether the number is formatted in
+scientific notation. It takes the following values:
+
+@table @code
+@item onlyForSmall
+Use scientific notation only when the number's magnitude is smaller
+than the value of the @code{small} attribute.
+
+@item whenNeeded
+Use scientific notation when the number will not otherwise fit in the
+available space.
+
+@item true
+Always use scientific notation. Not observed in the corpus.
+
+@item false
+Never use scientific notation. A number that won't otherwise fit will
+be replaced by an error indication (see the @code{errorCharacter}
+attribute). Not observed in the corpus.
+@end table
+@end defvr
+
+@defvr {Optional} small
+Only present when the @code{scientific} attribute is
+@code{onlyForSmall}, this is a numeric magnitude below which the
+number will be formatted in scientific notation. The values @code{0}
+and @code{0.0001} have been observed. The value @code{0} seems like a
+pathological choice, since no real number has a magnitude less than 0;
+perhaps in practice such a choice is equivalent to setting
+@code{scientific} to @code{false}.
+@end defvr
+
+@defvr {Optional} prefix
+@defvrx {Optional} suffix
+Specifies a prefix or a suffix to apply to the formatted number. Only
+@code{suffix} has been observed, with value @samp{%}.
+@end defvr
+
+@subsubheading String Attributes
+
+These attributes are used for formats when @code{baseFormat} is
+@code{string}.
+
+@defvr {Attribute} tryStringsAsNumbers
+When this is @code{true}, it is supposed to indicate that string
+values should be parsed as numbers and then displayed according to
+numeric formatting rules. However, in the corpus it is always
+@code{false}.
+@end defvr
+
+@node SPV Detail numberFormat Element
+@subsubsection The @code{numberFormat} Element
+
+Parent: @code{setFormat} @*
+Contents: @code{affix}@math{+}
+
+This element appears only in schema version 2.5 and earlier
+(@pxref{SPV Detail visualization Element}). Possibly this element
+could also contain @code{relabel} elements in a more diverse corpus.
+
+This element has the following attributes.
+
+@defvr {Attribute} maximumFractionDigits
+@defvrx {Attribute} minimumFractionDigits
+@defvrx {Attribute} minimumIntegerDigits
+@defvrx {Optional} scientific
+@defvrx {Optional} small
+@defvrx {Optional} suffix
+@defvrx {Optional} useGroupging
+The syntax and meaning of these attributes is the same as on the
+@code{format} element for a numeric format. @pxref{SPV Detail format
+element}.
+@end defvr
+
+@node SPV Detail stringFormat Element
+@subsubsection The @code{stringFormat} Element
+
+Parent: @code{setFormat} @*
+Contents: (@code{affix}@math{+} @math{|} @code{relabel}@math{+})?
+
+This element appears only in schema version 2.5 and earlier
+(@pxref{SPV Detail visualization Element}).
+
+This element has no attributes.
+
+@node SPV Detail dateTimeFormat Element
+@subsubsection The @code{dateTimeFormat} Element
+
+Parent: @code{setFormat} @*
+Contents: empty
+
+This element appears only in schema version 2.5 and earlier
+(@pxref{SPV Detail visualization Element}). Possibly this element
+could also contain @code{affix} and @code{relabel} elements in a more
+diverse corpus.
+
+The following attribute is required.
+
+@defvr {Attribute} baseFormat
+Either @code{dateTime} or @code{time}.
+@end defvr
+
+When @code{baseFormat} is @code{dateTime}, the following attributes
+are available.
+
+@defvr {Attribute} dayOfMonthPadding
+@defvrx {Attribute} dayPadding
+@defvrx {Attribute} dayType
+@defvrx {Attribute} hourFormat
+@defvrx {Attribute} hourPadding
+@defvrx {Attribute} mdyOrder
+@defvrx {Attribute} minutePadding
+@defvrx {Attribute} monthFormat
+@defvrx {Attribute} separatorChars
+@defvrx {Attribute} showDay
+@defvrx {Attribute} showHour
+@defvrx {Attribute} showMinute
+@defvrx {Attribute} showMonth
+@defvrx {Attribute} showSecond
+@defvrx {Attribute} showYear
+@defvrx {Attribute} yearAbbreviation
+The syntax and meaning of these attributes is the same as on the
+@code{format} element when that element's @code{baseFormat} is
+@code{dateTime}. @pxref{SPV Detail format Element}.
+@end defvr
+
+When @code{baseFormat} is @code{time}, the following attributes are
+available.
+
+@defvr {Attribute} hourFormat
+@defvrx {Attribute} hourPadding
+@defvrx {Attribute} minutePadding
+@defvrx {Attribute} monthFormat
+@defvrx {Attribute} separatorChars
+@defvrx {Attribute} showDay
+@defvrx {Attribute} showHour
+@defvrx {Attribute} showMinute
+@defvrx {Attribute} showMonth
+@defvrx {Attribute} showSecond
+@defvrx {Attribute} showYear
+@defvrx {Attribute} yearAbbreviation
+The syntax and meaning of these attributes is the same as on the
+@code{format} element when that element's @code{baseFormat} is
+@code{elapsedTime}. @pxref{SPV Detail format Element}.
+@end defvr
+
+@node SPV Detail affix Element
+@subsubsection The @code{affix} Element
+
+Parent: @code{format} or @code{numberFormat} or @code{stringFormat} @*
+Contents: empty
+
+Possibly this element could have @code{dateTimeFormat} as a parent in
+a more diverse corpus.
+
+This defines a suffix (or, theoretically, a prefix) for a formatted
+value. It is used to insert a reference to a footnote. It has the
+following attributes:
+
+@defvr {Attribute} definesReference
+This specifies the footnote number as a natural number: 1 for the
+first footnote, 2 for the second, and so on.
+@end defvr
+
+@defvr {Attribute} position
+Position for the footnote label. Always @code{superscript}.
+@end defvr
+
+@defvr {Attribute} suffix
+Whether the affix is a suffix (@code{true}) or a prefix
+(@code{false}). Always @code{true}.
+@end defvr
+
+@defvr {Attribute} value
+The text of the suffix or prefix. Typically a letter, e.g.@: @code{a}
+for footnote 1, @code{b} for footnote 2, @enddots{} The corpus
+contains other values: @code{*}, @code{**}, and a few that begin with
+at least one comma: @code{,b}, @code{,c}, @code{,,b}, and @code{,,c}.
+@end defvr
+
+@node SPV Detail relabel Element
+@subsubsection The @code{relabel} Element
+
+Parent: @code{format} or @code{stringFormat} @*
+Contents: empty
+
+Possibly this element could have @code{numberFormat} or
+@code{dateTimeFormat} as a parent in a more diverse corpus.
+
+This specifies how to display a given value. It is used to implement
+value labels and to display the system-missing value in a
+human-readable way. It has the following attributes:
+
+@defvr {Attribute} from
+The value to map. In the corpus this is an integer or the
+system-missing value @code{-1.797693134862316E300}.
+@end defvr
+
+@defvr {Attribute} to
+The string to display in place of the value of @code{from}. In the
+corpus this is a wide variety of value labels; the system-missing
+value is mapped to @samp{.}.
+@end defvr
+
+@node SPV Detail union Element
+@subsubsection The @code{union} Element
+
+Parent: @code{setCellProperties} @*
+Contents: @code{intersect}@math{+}
+
+This element represents a set of cells, computed as the union of the
+sets represented by each of its children.
+
+@subsubheading The @code{intersect} Element
+
+Parent: @code{union} @*
+Contents: @code{where}@math{+} @math{|} @code{intersectWhere}?
+
+This element represents a set of cells, computed as the intersection
+of the sets represented by each of its children.
+
+Of the two possible children, in the corpus @code{where} is far more
+common, appearing thousands of times, whereas @code{intersectWhere}
+only appears 4 times.
+
+Most @code{intersect} elements have two or more children.
+
+@subsubheading The @code{where} Element
+
+Parent: @code{intersect} @*
+Contents: empty
+
+This element represents the set of cells in which the value of a
+specified variable falls within a specified set.
+
+@defvr {Attribute} variable
+The @code{id} of a variable, e.g.@: @code{dimension0categories} or
+@code{dimension0group0map}.
+@end defvr
+
+@defvr {Attribute} include
+A value, or multiple values separated by semicolons,
+e.g.@: @code{0} or @code{13;14;15;16}.
+@end defvr
+
+@subsubheading The @code{intersectWhere}
+
+Parent: @code{intersect} @*
+Contents: empty
+
+The meaning of this element is unknown.
+
+@defvr {Attribute} variable
+@defvrx {Attribute} variable2
+The meaning of these attributes is unknown. In the four examples in
+the corpus they always take the values @code{dimension2categories} and
+@code{dimension0categories}, respectively.
+@end defvr