'static means two different things depending on where it appears, and conflating them is one of the most common sources of confusion in async Rust.

As a reference lifetime — &'static T — it means: this reference is valid for the entire run of the program. String literals qualify, because they are baked into the binary.

let s: &'static str = "baked into the binary";

This is a strong claim, and very few runtime values can make it.