v-slot default

Vue.js - The Progressive JavaScript Framework ... In addition, you can use JavaScript's native default value syntax to declare default values for the props.

As already mentioned, we can mark content with the default value v-slot:default to make it even more clear that the content belongs to the default slot.

The release of Vue 2.6 introduces a unified v-slot directive which can be used for normal or scoped slots. In this case, since you're using the default, unnamed slot, the property can be accessed via v-slot="{ signal }" ...