Which type of data does not come with additional attached metadata?

Raw data files typically do not come with additional attached metadata. This type of data is unprocessed and may contain information in its original format without any context or descriptions of the variables contained within it. Because it is the raw form of data collected directly from sources, it usually lacks the supplementary information about its source, collection method, or any transformation that may have been applied.

In contrast, data sources often include metadata that provides information about the data's origin, structure, and other relevant details. Processed data is typically enhanced with metadata to clarify how it has been transformed, what variables have been included, and the context in which it should be interpreted. Structured data usually comes with definitions and schemas that explain its organization and the meaning of the data elements, which is also a type of metadata.

Therefore, raw data files stand out as lacking this additional layer of information that aids in understanding and working with the data effectively.