Returns a filtered list of supported audio formats.

function wp_get_audio_extensions() {
	/**
	 * Filters the list of supported audio formats.
	 *
	 * @since 3.6.0
	 *
	 * @param string[] $extensions An array of supported audio formats. Defaults are
	 *                            'mp3', 'ogg', 'flac', 'm4a', 'wav'.
	 */
	return apply_filters( 'wp_audio_extensions', array( 'mp3', 'ogg', 'flac', 'm4a', 'wav' ) );
}