what is @vue:mounted syntax

[dengshenkk]

In this example , I sees a new "syntax", but I can't found any document for this "syntax"
@vue:mounted="({ el }) => el.focus()" , how do i understande this example?

https://cn.vuejs.org/examples/#todomvc

<input
  v-if="todo === editedTodo"
  class="edit"
  type="text"
  v-model="todo.title"
  @vue:mounted="({ el }) => el.focus()"
  @blur="doneEdit(todo)"
  @keyup.enter="doneEdit(todo)"
  @keyup.escape="cancelEdit(todo)"
>

[realByg]

not in the official doc but i found it in the migration guide

https://v3-migration.vuejs.org/breaking-changes/vnode-lifecycle-events.html

[PawRys]

@VUE:mounted="({ el }) => el.focus()"

how to make this TS compatible? I have Binding element 'el' implicitly has an 'any' type.