The content of this table holds the respawn data of creatures and gameobjects, even if the server crashes or is shut down manually.
Unix timestamp when the entity should be respawned.
MapID from Map.dbc where the entity should be spawned.
If the entity was killed/destroyed in an instance, this field holds the instance id where this entity should be respawned.
Each instance is different depending on the group so this field is vital in keeping track of which creatures/gameobjects should be respawned for which players at what time.