The website can be run locally using the Jekyll Ruby gem. You need to fully install Ruby; on Fedora that's achieved something like this:
dnf install rubygem-bundler
dnf install ruby-devel
Then install jekyll and start the web server as follows:
gem install jekyll
bundle exec jekyll serve
Please note that depending on the Ruby version you're running, you might need to specify the version of jekyll (and all its dependencies) using -v x.y.z with gem install, so that you get a version compatible with what this web site has been developed for. You should be getting clear error message by Ruby in case of version mismatches.
Please refer to https://jekyllrb.com/ for further informations on Jekyll.