Element: slot property - Web APIs | MDN - MDN Web Docs

mdn slot A named slot is a slot> element with a name attribute. Example. Let’s make an example using the slot> element along with the template> element. Partnering slot> with. element .slot = aString. A DOMString. The definition of 'slot' in that specification. The slot property of the Element interface returns the name of the shadow DOM slot attached to the element. A

mdnslot, 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.