draggable element must have an item slot
: The List Item element - HTML Demo - MDN Web Docs
Drag specific CSS properties that Muuri sets to the draggable item elements. Muuri automatically prefixes the properties before applying them to the element.
Why do people check in at the airport rather than online?
To schedule regular flights to and from that airport, an airline must have a slot pair.
Is there a way to have more accessory slots? - Terraria
An accessory slot defines the placement of the accessory on the item and any item can have 0-any accessory slots. You need to add an item (3D model) or item's under an accessory slot which the user can choose.