Within your alert subscription, you can view the revision log and subscription edits via this box on right hand side of your screen:
Revision Log is the specific to the alert, not specific to your subscription settings. It contains notes of changes to alert from recent revisions made by a CEO Juice Team Member. (We will not have records for anything prior to the new site launch, December 2015)
Install Log is Subscription specific. It is a record of all changes to the alert subscription you're looking at. It shows old and new values for each field changed, along with the user who made the change and timestamp. This could be the email addresses it sends to, variable values, revision number, etc.