/**
 * Fetches the CSS containing the @font-face declarations from Google Fonts.
 * The fetch has a user agent header with a modern browser to ensure we'll get .woff2 files.
 *
 * The env variable NEXT_FONT_GOOGLE_MOCKED_RESPONSES may be set containing a path to mocked data.
 * It's used to define mocked data to avoid hitting the Google Fonts API during tests.
 */
export declare function fetchCSSFromGoogleFonts(url: string, fontFamily: string, isDev: boolean): Promise<string>;