When an application is tuned to a specific DTD or XML Schema, it directly understands the significance of each element and attribute. For example, an HTML-sensitive Web browser recognizes and responds appropriately to each occurrence of the Image, Table and Form elements it encounters in a document. But when an application must perform specific tasks on data that conform to a variety of different models, the names of the significant elements and attributes are unlikely to be the same across all the models involved.
Harmonizing different models
Software that requires specific information from documents that conform to various models should expect to find the information in elements or attributes with different names.
For example, ...