How can i get router-view in TSX?

I looked at the source code, but i can not find the ‘router-view’ component.
In the install.js i can see the componnet of ‘router-view’ had registered but not export, so i can not use it as like this
import { RouterView } from 'vue-router'
or
import { RouterViewCfg } from 'vue-router'
const RouterView = Vue.component('RouterView', RouterViewCfg)

I got curious, so I found this,