draggable element must have an item slot - HTML Standard 888slots app

To make an element draggable, give the element a draggable attribute, and set an event listener for dragstart that stores the data being dragged.

The icon and main text element of an item are placed in slots automatically, and the description text element is placed using the slot prop to specify a named area.

The slot global attribute assigns a slot in a shadow DOM shadow tree to an element: An element with a slot attribute is assigned to the slot created by the element whose name attribute's value matches that slot attribute's value.

Drag specific CSS properties that Muuri sets to the draggable item elements. Muuri automatically prefixes the properties before applying them to the element.