vue3-core/packages/vue-compat/src/runtime.ts

// This entry exports the runtime only, and is built as
// `dist/vue.esm-bundler.js` which is used by default for bundlers.
import { createCompatVue } from './createCompatVue'
import { warn } from '@vue/runtime-core'

const Vue = createCompatVue()

Vue.compile = (() => {
  if (__DEV__) {
    warn(
      `Runtime compilation is not supported in this build of Vue.` +
        (__ESM_BUNDLER__
          ? ` Configure your bundler to alias "vue" to "@vue/compat/dist/vue.esm-bundler.js".`
          : __ESM_BROWSER__
          ? ` Use "vue.esm-browser.js" instead.`
          : __GLOBAL__
          ? ` Use "vue.global.js" instead.`
          : ``) /* should not happen */
    )
  }
}) as any

export default Vue