a bit late for the party ...
In Splunk Enterprise under Settings - Source Types you can list, create and edit sourcetypes options in the according props.conf .
The docs talk about the process to modify sourcetypes in Splunk Enterprise here http://docs.splunk.com/Documentation/Splunk/latest/Data/Managesourcetypes and for Splunk Cloud here http://docs.splunk.com/Documentation/SplunkCloud/latest/Data/Managesourcetypes
Hope this helps ...
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