Using templates and slots - Web APIs | MDN - MDN Web Docs

mdn slot We'll discuss using the template> and slot> elements, the slot attribute, and JavaScript to create a template with an encapsulated Shadow DOM. We'll then re-use. When the slot's containing component gets rendered, the slot is rendered with the custom element's child that has a matching slot attribute. A named slot is a slot> element

mdnsport, When the slot's containing component gets rendered, the slot is rendered with the custom element's child that has a matching slot attribute. A named slot is a slot> element.