How does the FSL managed package relate to Salesforce core and what licenses are needed?

Field Service Lightning is a managed package installed on top of a Salesforce org (Sales Cloud or Service Cloud). It adds the FSL objects, the Dispatcher Console, and the scheduling engine. License types:

1. Field Service Dispatcher — for dispatchers using the Dispatcher Console; includes Gantt and optimization access.
2. Field Service Technician — for field workers using the mobile app; allows Work Order and mobile features.
3. Field Service Scheduling — for scheduling optimizer and resource management without console access. The FSL managed package version must be updated separately from Salesforce core releases. Core CRM functionality (Accounts, Contacts, Cases) is available without FSL licenses; only FSL-specific objects and features require FSL licenses.