The FORT validator is an MIT-licensed RPKI Relying Party, offered as part of the FORT project. It is a service that performs the validation of the entire RPKI repository, and which serves the resulting ROAs for easy access by your routers.
As of 2023-06-22, development has resumed. You might want to bump your desired patches and features in the tracker.
Version 1.6.1 is the latest official release. To fetch or review it, visit the GitHub release.