Starting with the basics, did you install the app? If so, can you say more about your search and your environment, maybe provide steps to reproduce, so the community can try to answer your question?
I see the problem, you want a dash, not an underscore before the version string: tar xvzf importutil-1.0-beta2.tar.gz (the github page does have it wrong).
I downloaded the app trying to install it using this command it is giving me errors and not installing it..
tar xvzf importutil_.tar.gz $SPLUNK_HOME/etc/apps
