The call graphs in transaction snapshots of the Node.js, PHP, and Python agents have an artificial root node named {request}.

For Python and PHP, the purpose of this node is to reconcile time differences between the total business transaction time and the sum of the observed call graph nodes, to act as a single entry point for the call graph, and to contain any exit calls which could not be attributed to any other nodes.

For Node.js, the {request} node in a business transaction call graph signals the availability of a process snapshot call graph that intersects with the transaction snapshot. If there is no {request} node, no process snapshot is available. See Process Snapshots and Business Transaction Snapshots.