The source code is available at the following url as a collection of git repositories :
The repository clowder containes the web frontend and is required. It should be cloned using the following command:
> git clone https://opensource.ncsa.illinois.edu/stash/scm/cats/clowder.git
Most of the other repositories include specific extractors. Basic extractors are available in extractors-core:
> git clone https://opensource.ncsa.illinois.edu/stash/scm/cats/clowder.git