A secretive Pentagon program that started on Trump’s last day in office just ended. The mystery has not.

On Friday, the Pentagon told The Post that the pilot program, which it previously had characterized as a cybersecurity measure designed to detect unspecified “vulnerabilities” and “prevent unauthorized use of DoD IP address space,” was over. Parts of the Internet once managed by Global Resource Systems, the Pentagon said, now were being overseen by the Department of Defense Information Network, known by the acronym DODIN and part of U.S. Cyber Command, based at Fort Meade.