Diagrams of how Search Head works in the Splunk platform

[AtherAD]

The purpose of this query is to create legacy diagrams of how the search head works in Splunk. I want to know the internal flow of the search head so anyone can use it in a future LLD or flow diagram. 

[richgalloway]

There are no diagrams of how a Splunk search head works.  All we need to know is that user queries are sent to indexers and the responses from the indexers are collated and returned to the user.  Any flow diagram would have a single box labeled "Search Head".