A Tableau Data Source (.tableaudatasource) file contains metadata and connection information for connecting Tableau to various data sources. It does not contain the actual data itself, but rather instructions on how to access and interpret the data. This includes information such as the data source type (e.g., Excel, CSV, SQL Server, Oracle), server name, database name, table names, field names, data types, and any custom calculations or relationships defined within Tableau. These files are used to streamline the process of connecting to data and ensure consistency across different Tableau workbooks and dashboards. They allow users to quickly and easily connect to the same data source without having to reconfigure the connection settings each time. Sharing .tableaudatasource files is a common practice for collaborating on Tableau projects and ensuring that everyone is using the same data definitions. The file can also contain embedded credentials, though this is generally discouraged for security reasons. When opened in Tableau, the data source connection is established, and the user can begin building visualizations and analyses.