|Metadata, conditional processing, and indexing / Condition (or select) attributes|
The props attribute is only used for specialising new metadata attributes.
The props attribute is technically one of the select (or condition) attributes, designed for filtering and flagging during publishing. However, the props attribute is not intended to be used within a topic or document. It is provided to be used as the basis for specialised condition attributes.
Do not use this attribute when authoring DITA topics or maps.