WordPress/wp-includes/vars.php

<?php

// On which page are we ?
if ( preg_match('#([^/]+\.php)$#', $PHP_SELF, $self_matches) ) {
	$pagenow = $self_matches[1];
} elseif ( strpos($PHP_SELF, '?') !== false ) {
	$pagenow = explode('/', $PHP_SELF);
	$pagenow = trim($pagenow[(sizeof($pagenow)-1)]);
	$pagenow = explode('?', $pagenow);
	$pagenow = $pagenow[0];
} else {
	$pagenow = 'index.php';
}

// Simple browser detection
$is_lynx = $is_gecko = $is_winIE = $is_macIE = $is_opera = $is_NS4 = false;

if (strpos($_SERVER['HTTP_USER_AGENT'], 'Lynx') !== false) {
	$is_lynx = true;
} elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'Gecko') !== false) {
	$is_gecko = true;
} elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Win') !== false) {
	$is_winIE = true;
} elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Mac') !== false) {
	$is_macIE = true;
} elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'Opera') !== false) {
	$is_opera = true;
} elseif (strpos($_SERVER['HTTP_USER_AGENT'], 'Nav') !== false && strpos($_SERVER['HTTP_USER_AGENT'], 'Mozilla/4.') !== false) {
	$is_NS4 = true;
}

$is_IE = ( $is_macIE || $is_winIE );

// Server detection
$is_apache = ((strpos($_SERVER['SERVER_SOFTWARE'], 'Apache') !== false) || (strpos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false)) ? true : false;
$is_IIS = (strpos($_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS') !== false) ? true : false;

$wp_header_to_desc = apply_filters( 'wp_header_to_desc_array', array(
	100 => 'Continue',
	101 => 'Switching Protocols',

	200 => 'OK',
	201 => 'Created',
	202 => 'Accepted',
	203 => 'Non-Authoritative Information',
	204 => 'No Content',
	205 => 'Reset Content',
	206 => 'Partial Content',

	300 => 'Multiple Choices',
	301 => 'Moved Permanently',
	302 => 'Found',
	303 => 'See Other',
	304 => 'Not Modified',
	305 => 'Use Proxy',
	307 => 'Temporary Redirect',

	400 => 'Bad Request',
	401 => 'Unauthorized',
	403 => 'Forbidden',
	404 => 'Not Found',
	405 => 'Method Not Allowed',
	406 => 'Not Acceptable',
	407 => 'Proxy Authentication Required',
	408 => 'Request Timeout',
	409 => 'Conflict',
	410 => 'Gone',
	411 => 'Length Required',
	412 => 'Precondition Failed',
	413 => 'Request Entity Too Large',
	414 => 'Request-URI Too Long',
	415 => 'Unsupported Media Type',
	416 => 'Requested Range Not Satisfiable',
	417 => 'Expectation Failed',

	500 => 'Internal Server Error',
	501 => 'Not Implemented',
	502 => 'Bad Gateway',
	503 => 'Service Unavailable',
	504 => 'Gateway Timeout',
	505 => 'HTTP Version Not Supported'
) );

?>