Custom Events can be any specific in-game action your user performs. They allow you to track the player behavior that Unity Analytics does not track automatically, and for which there is no Standard Event. Each Custom Event can have up to ten parameters. There are no required parameters.
In general, you should only using Custom Events when no suitable Standard Event is defined. Because Standard Events have a defined context, Unity can provide better analysis and visualization support than for Custom Events.
2018–03–02 Page published 2018–03–02 - Service compatible with Unity 5.2 onwards at this date but version compatibility may be subject to change
New feature in 5.2
Standard Events added as Unity package