/**
 * Does this environment declare a UTF-8 locale? The POSIX variables are checked in the order the C
 * library resolves them (LC_ALL overrides LC_CTYPE overrides LANG).
 *
 * Windows terminals declare none of these and are handled as UTF-8: modern Windows Terminal and
 * PowerShell render it, and the failure this guards against is a Unix locale that says C/POSIX.
 */
export declare function terminalRendersUnicode(env?: NodeJS.ProcessEnv): boolean;
/**
 * Rewrite a string so a non-UTF-8 terminal can read it. A no-op when the terminal handles Unicode,
 * so the good case keeps every glyph it was designed with.
 *
 * Characters with no declared fallback are replaced with `?` rather than passed through: passing
 * them through is what produced `���` in the first place, and one `?` is at least legible as
 * "something did not survive".
 */
export declare function forTerminal(text: string, env?: NodeJS.ProcessEnv): string;