Metadata attribute group

@props: Root attribute from which new metadata attributes can be specialized. This is a property attribute which supports conditional processing for filtering or flagging. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
@base: A generic attribute that has no specific purpose. It is intended to act as a base for specialized attributes that have a simple value syntax like the conditional processing attributes (one or more alphanumeric values separated by whitespace), but is not itself a filtering or flagging attribute.

The @props and @base attributes each take a space-delimited set of values. However, when acting as a container for generalized attributes, the attribute values will be more complex; see Attribute generalization for more details.

@platform: Indicates operating system and hardware. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
@product: Contains the name of the product to which the element applies. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
@audience: Indicates the intended audience for the element. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
@otherprops: This attribute can be used for any other properties that might be needed to describe an audience, or to provide selection criteria for the element. Alternatively, the @props attribute can be specialized to provide a new metadata attribute instead of using the general @otherprops attribute. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.

The @audience, @platform, @product, and @otherprops attributes are property attributes which support conditional processing for filtering or flagging. Each takes a space-delimited set of values, with optional groups of space-delimited properties. Although these attributes are not specialized and not specializeable, the group syntax matches that for generalized attributes in Attribute generalization.

@deliveryTarget: The intended delivery target of the content, for example "html", "pdf", or "epub". This attribute is a replacement for the now deprecated @print attribute.
The @deliveryTarget attribute is specialized from the @props attribute. It is defined in the deliveryTargetAttDomain, which is integrated into all OASIS-provided document-type shells. If this domain is not integrated into a given document-type shell, the @deliveryTarget attribute will not be available.

@importance: A range of values that describe an importance or priority attributed to an element. For example, in steps of a task, the attribute indicates whether a step is optional or required. This attribute is not used for DITAVAL-based filtering or flagging; applications might use the importance value to highlight elements. Allowable values are: obsolete, deprecated, optional, default, low, normal, high, recommended, required, urgent, and -dita-use-conref-target.
@rev: Indicates a revision level of an element that identifies when the element was added or modified. It can be used to flag outputs when it matches a run-time parameter; it cannot be used for filtering. It is not sufficient to be used for version control. If no value is specified, but the attribute is specified on an ancestor within a map or within the related-links section, the value will cascade from the closest ancestor.
@status: The modification status of the current element. Allowable values are: new, changed, deleted, unchanged, and -dita-use-conref-target.