The bubble property specifies the DayPilot.Bubble object that will be used to show event details on hover.
null1. A simple bubble that displays content specified using the bubbleHtml property of a card data object.
Kanban config:
{
  bubble: new DayPilot.Bubble(),
  // ...
}2. A Bubble with content dynamically loaded from an API endpoint.
Kanban config:
{
  bubble: new DayPilot.Bubble({
    onLoad: async (args) => {
        const card = args.source;
        args.async = true;
        
        const {data} = await DayPilot.Http.get(`/api/bubbleContent/${card.data.id}`);
        
        args.html = data.html;
        args.loaded();
    }
  }),
  // ...
}