The Data.gov Theme extension provides the official visual identity and user experience design for the United States federal government’s primary open data portal at Data.gov, implementing U.S. Web Design System (USWDS) standards, federal branding requirements, and accessibility compliance for comprehensive government data sharing. This official government theme incorporates federal visual identity including official U.S. government colors, typography, logos, and design patterns while maintaining strict compliance with federal accessibility standards (Section 508), security requirements, and government digital service guidelines. The extension includes specialized page layouts optimized for federal data presentation, government-specific templates for agency datasets, and integration with federal digital infrastructure and inter-agency data sharing systems. Advanced features include federal agency organization structures, government-specific metadata requirements, and integration with federal identity and authentication systems including login.gov and PIV card authentication. The theme provides specialized widgets for displaying federal statistics, agency performance data, and government transparency information with visual representations appropriate for public understanding of federal operations and data. Customizations include federal agency-specific dataset categorization, enhanced search functionality with government organizational filtering and federal data classification, and mobile-optimized interfaces designed for citizen access to federal government services and information. Integration capabilities include connections to federal data management systems, agency databases, and government-wide platforms for comprehensive federal data sharing and transparency initiatives. Administrative features provide content management tools for federal agency staff, workflow integration with government systems, and comprehensive analytics for federal data usage tracking and government transparency reporting. Essential for the U.S. federal government’s open data initiative, supporting transparency requirements under federal law, enhancing citizen access to government information, and promoting democratic participation through improved data accessibility and government accountability in the world’s largest government open data portal serving millions of citizens, researchers, and organizations seeking federal government data.