In DITA documentation, specialization is typically mapped using subject scheme maps or specializations modules. Here’s how it works:

• Subject Scheme Maps: Specializations can be mapped using subject scheme maps. Subject schemes provide a way to categorize and organize topics based on their subject or domain. By customizing subject scheme maps, organizations can incorporate specialized categories and metadata specific to their needs.
• Specialization Modules: Specializations are implemented using specialized DITA modules. These modules contain the definitions of custom elements, attributes, and rules associated with a particular specialization. The modules are referenced in DITA topics that require specialized content.

When content creators create DITA topics, they reference the relevant specialization modules and apply the custom elements and attributes within those topics. The subject scheme maps guide how these specialized topics are categorized, organized, and related to each other.

Example:

In a DITA documentation project for the automotive industry, a subject scheme map is created to categorize topics into domains like “Car Models,” “Maintenance,” and “Safety Features.” Specialization modules define elements specific to these domains, such as <engine-details> and <safety-guidelines>. Topics related to car models would reference the “Car Models” subject scheme category and incorporate elements from the “Car Models” specialization module.