Function actor_handle 

pub fn actor_handle(actor_hex: &str) -> Option<String>

Decode an actor id back to the handle the authoring process chose for itself, when it did. ActorId::from(&[u8]) stores the bytes verbatim, so set_actor(ActorId::from(app_id.as_bytes())) leaves the UTF-8 of app_id in the hex. Returns None for anything not a plausible handle (odd-length /non-hex input, non-UTF-8, control chars, empty, or too long); a 32-byte public key almost never survives this filter.