I am going in circles looking for an installable iRules editor

A zip? whatever - someone else asked the question - how do you install this? The answer was: double click on the msi file, assuming you're in a Windows environment. Only, there is no MSI in iRuler-Source.zip. That's the only iRule editor download I can find. I'm probably missing something basic, I understand - can someone point me to a URL to download something iRuleEditorish that I can INSTALL by running the msi?