There is a hidden file NAME.zip for each directory NAME. This file contains the compressed (zipped) content of this directory. You can retrieve it as:
https://server.ccl.net/cca/software/SOURCES/C/NAME.zip
For example, for directory potential_energy_surface_O_C2H2, enter the URL
https://server.ccl.net/cca/software/SOURCES/FORTRAN90/potential_energy_surface_O_C2H2.zip
into your browser to retrieve it to your local computer.