Variable: SHADOW_FAILURE_KINDS

const SHADOW_FAILURE_KINDS: readonly ["unavailable", "disabled", "rejected", "unknown"]

Every kind of a failed ShadowSubmitOutcome, for an app that maps each to its own text (Record<ShadowFailureKind, string>): unavailable (retryable), disabled (the shadow route answered 400: the request is not a dark-swappable one, e.g. SHADOW_UNSUPPORTED_TYPE; Shadow Swaps themselves are enabled in every environment), rejected (carries the gateway's message) and unknown.