In SERVER-83293, we added a file and SCons target for search_index_common, which prompted conversation about the naming of search_index_helper. gil.alon@mongodb.com suggested "search_index_helpers_interface" or "search_index_process_interface". From GitHub PR comment:

I think search_index_helpers_interface or search_index_process_interface is more representative of what the search index helpers files do. They work similarly to the process interfaces by having different implementations if we are on a shard or not.