Last year, a successful Freedom of Information request for the United States enterprise data inventory by the Sunlight Foundation was a big win for open government, nudging Uncle Sam towards a better information policy through some creative legal arguments. Today, the federal government started releasing its enterprise indices at data.gov. You can browse the data for individual agencies, like the feed for the Office for Personnel Management, using a JSON viewer like this one.

“Access to this data will empower journalists, government officials, civic technologists, innovators and the public to better hold government accountable,” said Sunlight Foundation president Chris Gates, in a statement. “Previously, it was next to impossible to know what and how much data the government has, and this is an unprecedented window into its internal workings. Transparency is a bedrock principle for democracy, and the federal government’s response to Sunlight’s Freedom of Information request shows a strong commitment to open data. We expect to see each of these agencies continue to proactively release their data inventories.”

Understanding what data an organization holds is a critical first step in deciding how it should be stored, analyzed or published, shifting towards thinking about data as an asset. That’s why President Barack Obama’s executive order requiring federal agencies to catalog the data they have was a big deal. When that organization is a democratic government and the data in question was created using taxpayer funds, releasing the inventory of the data sets that it holds is a basic expression of open and accountable government.