Confusing example on covariance

I'm not sure if this is an issue or not, but I can't get my head round it.

I have a copy of the first printing, and on page 16, first paragraph we have a couple of sentences explaining that `&'a T` is covariant in `'a`, which I get. But then there is this sentence:

> `&'a T` is also covariant in `T`, so you can pass a `&Vec<&' static str>` to a function that takes `&Vec<'a str>`.

I think I know what the first bit means, but I don't understand how the example relates to it. It shows that `&Vec` is covariant in `T`, but that's not obviously the same thing.

Or is T here intended to be `Vec<&'a str>`? If so, we have two unrelated uses of `'a`.