one of the WordPress mobile apps.
	 *
	 * @return bool
	 */
	public static function is_mobile_app() {

		if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
			return false;
		}

		$agent = strtolower( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- This is validating.

		if ( isset( $_SERVER['X_USER_AGENT'] ) && preg_match( '|wp-webos|', $_SERVER['X_USER_AGENT'] ) ) { // phpcs:ignore WordPress.Security.ValidatedSanitizedInput -- This is validating.
			return true; // Wp4webos 1.1 or higher.
		}

		$app_agents = array( 'wp-android', 'wp-blackberry', 'wp-iphone', 'wp-nokia', 'wp-webos', 'wp-windowsphone' );
		// the mobile reader on iOS has an incorrect UA when loading the reader
		// currently it is the default one provided by the iOS framework which
		// causes problems with 2-step-auth
		// User-Agent   WordPress/3.1.4 CFNetwork/609 Darwin/13.0.0.
		$app_agents[] = 'wordpress/3.1';

		foreach ( $app_agents as $app_agent ) {
			if ( false !== strpos( $agent, $app_agent ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Detects if the current browser is Nintendo 3DS handheld.
	 *
	 * Example: Mozilla/5.0 (Nintendo 3DS; U; ; en) Version/1.7498.US
	 * can differ in language, version and region
	 */
	public static function is_Nintendo_3DS() {
		if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
			return false;
		}

		$ua = strtolower( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- This is validating.
		if ( strpos( $ua, 'nintendo 3ds' ) !== false ) {
			return true;
		}
		return false;
	}

	/**
	 * Was the current request made by a known bot?
	 *
	 * @return boolean
	 */
	public static function is_bot() {
		static $is_bot = null;

		if ( empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
			return false;
		}

		if ( $is_bot === null ) {
			$is_bot = self::is_bot_user_agent( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- This is validating.
		}

		return $is_bot;
	}

	/**
	 * Is the given user-agent a known bot?
	 * If you want an is_bot check for the current request's UA, use is_bot() instead of passing a user-agent to this method.
	 *
	 * @param string $ua A user-agent string.
	 *
	 * @return boolean
	 */
	public static function is_bot_user_agent( $ua = null ) {

		if ( empty( $ua ) ) {
			return false;
		}

		$bot_agents = array(
			'alexa',
			'altavista',
			'ask jeeves',
			'attentio',
			'baiduspider',
			'bingbot',
			'chtml generic',
			'crawler',
			'fastmobilecrawl',
			'feedfetcher-google',
			'firefly',
			'froogle',
			'gigabot',
			'googlebot',
			'googlebot-mobile',
			'heritrix',
			'httrack',
			'ia_archiver',
			'irlbot',
			'iescholar',
			'infoseek',
			'jumpbot',
			'linkcheck',
			'lycos',
			'mediapartners',
			'mediobot',
			'motionbot',
			'msnbot',
			'mshots',
			'openbot',
			'pss-webkit-request',
			'pythumbnail',
			'scooter',
			'slurp',
			'snapbot',
			'spider',
			'taptubot',
			'technoratisnoop',
			'teoma',
			'twiceler',
			'yahooseeker',
			'yahooysmcm',
			'yammybot',
			'ahrefsbot',
			'pingdom.com_bot',
			'kraken',
			'yandexbot',
			'twitterbot',
			'tweetmemebot',
			'openhosebot',
			'queryseekerspider',
			'linkdexbot',
			'grokkit-crawler',
			'livelapbot',
			'germcrawler',
			'domaintunocrawler',
			'grapeshotcrawler',
			'cloudflare-alwaysonline',
			'cookieinformationscanner', // p1699315886066389-slack-C0438NHCLSY
			'facebookexternalhit', // https://www.facebook.com/externalhit_uatext.php
			'feedburner',
			'yacybot', // http://yacy.net/bot.html
			'trendictionbot',  // http://www.trendiction.de/bot;
			'elisabot',
			'linkfluence', // http://linkfluence.com/
			'semrushbot', // https://www.semrush.com/bot/
			'archive.org_bot', // http://archive.org/details/archive.org_bot
			'ezlynxbot', // https://www.ezoic.com/bot
			'siteauditbot', // https://www.semrush.com/bot/
			'snapchat', // https://developers.snap.com/robots
			'applebot', // https://support.apple.com/en-ca/HT204683
			'bne.es_bot', // https://www.bne.es/es/colecciones/archivo-web-espanola/aviso-webmasters
			'google-safety;', // https://www.google.com/bot.html
			'mojeekbot', // https://www.mojeek.com/bot.html
			'linkwalker', // https://www.linkwalker.com/
		);

		foreach ( $bot_agents as $bot_agent ) {
			if ( false !== stripos( $ua, $bot_agent ) ) {
				return true;
			}
		}

		return false;
	}
}