@shopify/app-bridge-host/store/reducers/embeddedApp/legacy/actions.d.ts

App Bridge Host contains middleware and components that are meant to be consumed by the app's host. The middleware and `Frame` component are responsible for facilitating messages posted between the client and host, and used to act on actions sent from the

export declare const SET_LEGACY = "PRIVATE_APP::SET_LEGACY";
export interface SetLegacyAction {
    readonly type: typeof SET_LEGACY;
    payload: boolean;
}