I can't explain this simpler but Event Sourcery is a PHP event sourcing and CQRS framework that emphasizes easy-of-development and personal privacy protection.
Events in Domain Driven Design are messages, information, something that happens.
The identity focusses on these messages which can be simple or complex and consist of multiple elements.
The orbs in the EVENT SOURCERY identity represent these events, each event can have multiple layers. Multiple layers and colours represent a more complex message. The orbs can be used both simple and complex throughout all media.