Action Log for Installed Bases and Installed Base Components 
You use the action log function for installed bases and installed base components to get an overview of all of the changes that have been made during the processing of an installed base. Changes made to fields and transactions, such as the deletion of a component, are listed in the action log.
You have defined which changes made to the installed base should be recorded in the action log in Customizing for Customer Relationship Management under .
For more information, see the documentation for this Customizing activity.