Which item is NOT typically included in the attached metadata of a data source?

In the context of data sources, metadata typically includes details that enhance the understanding and usability of the data. Variable roles, variable measurement levels, and data table roles are all fundamental aspects of metadata that describe the characteristics and intended use of the data.

Variable roles refer to how each variable is intended to be used in modeling, such as whether it is an input predictor or the target variable. Variable measurement levels specify the type of data (e.g., nominal, ordinal, interval, ratio), which is crucial for understanding how to analyze and interpret the data correctly. Data table roles indicate the purpose of the specific table within a dataset, such as whether it serves as a training set or a validation set.

In contrast, data processing time is not a standard component of the metadata attached to a data source. While knowing when data was processed can be useful for tracking data lineage or understanding its freshness, it does not directly contribute to the structural or functional understanding of the data itself. Thus, it is not typically included in metadata, making it the correct answer to the question regarding what is NOT included.