protected function checkBrowsers()
    {
        return (
            // well-known, well-used
            // Special Notes:
            // (1) Opera must be checked before FireFox due to the odd
            //     user agents used in some older versions of Opera
            // (2) WebTV is strapped onto Internet Explorer so we must
            //     check for WebTV before IE
            // (3) (deprecated) Galeon is based on Firefox and needs to be
            //     tested before Firefox is tested
            // (4) OmniWeb is based on Safari so OmniWeb check must occur
            //     before Safari
            // (5) Netscape 9+ is based on Firefox so Netscape checks
            //     before FireFox are necessary
            // (6) Vivalid is UA contains both Firefox and Chrome so Vivalid checks
            //     before Firefox and Chrome
            $this->checkBrowserWebTv() ||
            $this->checkBrowserEdge() ||
            $this->checkBrowserInternetExplorer() ||
            $this->checkBrowserOpera() ||
            $this->checkBrowserGaleon() ||
            $this->checkBrowserNetscapeNavigator9Plus() ||
            $this->checkBrowserVivaldi() ||
            $this->checkBrowserYandex() ||
            $this->checkBrowserFirefox() ||
            $this->checkBrowserChrome() ||
            $this->checkBrowserOmniWeb() ||

            // common mobile
            $this->checkBrowserAndroid() ||
            $this->checkBrowseriPad() ||
            $this->checkBrowseriPod() ||
            $this->checkBrowseriPhone() ||
            $this->checkBrowserBlackBerry() ||
            $this->checkBrowserNokia() ||

            // common bots
            $this->checkBrowserGoogleBot() ||
            $this->checkBrowserMSNBot() ||
            $this->checkBrowserBingBot() ||
            $this->checkBrowserSlurp() ||

            // Yandex bots
            $this->checkBrowserYandexBot() ||
            $this->checkBrowserYandexImageResizerBot() ||
            $this->checkBrowserYandexBlogsBot() ||
            $this->checkBrowserYandexCatalogBot() ||
            $this->checkBrowserYandexDirectBot() ||
            $this->checkBrowserYandexFaviconsBot() ||
            $this->checkBrowserYandexImagesBot() ||
            $this->checkBrowserYandexMediaBot() ||
            $this->checkBrowserYandexMetrikaBot() ||
            $this->checkBrowserYandexNewsBot() ||
            $this->checkBrowserYandexVideoBot() ||
            $this->checkBrowserYandexWebmasterBot() ||

            // check for facebook external hit when loading URL
            $this->checkFacebookExternalHit() ||

            // WebKit base check (post mobile and others)
            $this->checkBrowserSamsung() ||
            $this->checkBrowserSilk() ||
            $this->checkBrowserSafari() ||

            // everyone else
            $this->checkBrowserNetPositive() ||
            $this->checkBrowserFirebird() ||
            $this->checkBrowserKonqueror() ||
            $this->checkBrowserIcab() ||
            $this->checkBrowserPhoenix() ||
            $this->checkBrowserAmaya() ||
            $this->checkBrowserLynx() ||
            $this->checkBrowserShiretoko() ||
            $this->checkBrowserIceCat() ||
            $this->checkBrowserIceweasel() ||
            $this->checkBrowserW3CValidator() ||
            $this->checkBrowserPlayStation() ||
            $this->checkBrowserIframely() ||
            $this->checkBrowserCocoa() ||
            $this->checkBrowserMozilla() /* Mozilla is such an open standard that you must check it last */
        );
    }