iROCK is available at https://sci-ops.gitlab.io/irock/ - this is a version hosted by GitLab. You can also download all files to your local PC, and run it from there. To do that, simply visit the repository at https://gitlab.com/sci-ops/irock and click the download button at the right-hand side (next to the “History” and “Find file” buttons). You can download the archive, unpack it on your PC, store the files somewhere, and then double-click the “index.html” file in the “iROCK” directory.
Note that iROCK is Free/Libre Open Source Software (FLOSS), which means that you can inspect the source code, and add functionality, if desired (see the repository at https://gitlab.com/sci-ops/irock).