[Reference: Create and View Custom ARC Graphs | Salesforce Help, Explanation: A flex card is a Lightning web component that displays information about a node in the Actionable Relationship Center (ARC). A flex card can be customized to show different fields, actions, and related lists for different node types. Developers can reference the flex card in the Display properties of the custom ARC relationship graph to configure how each node is displayed in ARC., , , , , ]