The structure has been changed so that all data is now available for download in just 4 ZIP files to improve user-friendliness.
Links:
https://www.epc.ed.tum.de/td/forschung/ddt/database/
https://www.epc.ed.tum.de/td/forschung/ddt/database/homogeneous-h2-air-mixtures/
https://www.epc.ed.tum.de/td/forschung/ddt/database/homogeneous-h2-co-air-mixtures/
Happy downloading!