The Change Auditor agent will create the ScriptingAgentConfig.xml if it does not exist or will otherwise update the ScriptingAgentConfig.xml if it does exist.
The Change Auditor agent adds a custom Cmdlet Handler to the existing or new ScriptingAgentConfig.xml file. The size of the file will vary depending on whether the Cmdlet Handler was added to a new or existing file on each Exchange server.
In some cases there are two Cmdlet Handlers Dell-ChangeAuditor-CmdletHandler and Quest-ChangeAuditor-CmdletHandler, likely due to an upgrade. Although this will not cause any issue it does affect the size as well.
This does not account for other applications that may add there configuration to this file.