@Esky73, | addinfo command adds search related metadata info to the search results so that the same can be reused. I think the documentation is fairly detailed as to what each for the info_* fields do
info_min_time : Earliest time selected for the search you ran (this would be the earliest time from the Time Picker that you run or else if you have used `earliest` parameter in the base search)
info_max_time : Latest time selected for the search you ran (this would be the latest time from the Time Picker that you run or else if you have used `latest` parameter in the base search)
info_sid : The Search ID of the search job that generated the event/s. This will help you re-run the search or pull the results from the search using this ID. (REST endpoints reference are listed here: http://docs.splunk.com/Documentation/Splunk/latest/RESTTUT/RESTsearches#REST_endpoints_for_searches)
info_search_time : The time when the Search job was executed. This would be the same as info_max_time when your latest time is `now()` or `@s`
If you want to see these values and understand how they work you can change the second query in the addinfo reference documentation like the following and re-run the search with different Time ranges:
Actually in the query the pipe | eval latest_age = info_max_time - latest_time, is used to calculate theage of last event received per host, using latest event received per host (i.e. latest_time) by subtracting it from latest time which is being seen usinglatest from the time range picker` (i.e. info_max_time). Let us know if you require further details.