I am thinking the idea behind the rules of ownership in Rust,
and what makes me confused is that:
Given

• reference is borrowing instead of owning;
• there is only one owner of
  data;

The following code which use a mutable reference to change the data owner is still workable. Doesn’t this violate the previous rules ?

fn main() {
  let mut v = vec![1, 2, 3];
  //let ref_v = &v;
  let ref_i = &mut v[0];
  *ref_i = 10;
  println!("{v:?}");

  let mut v2 = vec![1, 2, 3];
  //let ref_v = &v;
  let ref_v2 = &mut v2;
  *ref_v2 = vec![10, 20, 30];
  println!("{v2:?}");
}