Meaning of v-slot:activator="{on}"

vuetify

#1

Hi, as the title says: What is the meaning of v-slot:activator="{on}"?
I am currently using Vuetify to create a toolbar, but in Internet Explorer I only get an error, and have found out that it happends due to v-slot:activator="{on}". But I have no idea what this part actually does:

        <template v-slot:activator="{ on }">
          <v-toolbar-title v-on="on">
            <span>All</span>
            <v-icon dark>arrow_drop_down</v-icon>
          </v-toolbar-title>
        </template>

It works fine in Chrome and Firefox. In the example code the “on” attribute does not seem to be a data property.

```
<script>
  export default {
    data: () => ({
      items: [
        'All', 'Family', 'Friends', 'Coworkers'
      ]
    })
  }
</script>
```

#2

In this case you are rendering the contents of a <template> into the 'activator' named slot of whichever component this template is defined inside.

The named slot activator is also a scoped slot and you are destructuring the slot props and extracting the on property from those slot props.