How did you come across this site? Is this your site? When you see urls like the one you provided that doesn’t have the page type listed (.php, .asp, .aspx, .html, etc) that is a folder and not a file. The url is pointing to a default page for that directory. The information after the ‘?’ is information that gets passed through to the page to use. Here is an example so you can understand:
If I have a directory called scripts and in that directory I have the script index.php, index.php is the server’s default script and if you access the directory without a page in the url, you will go straight to the default script. So I can call www.domain.com/script and it’ll automatically point to the index.php. Now in your case the site is pointing to the default script and sending information to it. (www.domain.com/script?var1=value1&var2=value2 is the same as saying www.domain.com/script/index.php?var1=value1&var2=value2)
Now if the website isn’t allowing people to access that directory, then it’s not meant to be accessed and there is no way to view the page. Also, the script might be in a secure area requiring authentication and you need to have proper authentication to view it. Either way, unless this is your site, we cannot assist you in your problem. Please contact that site’s administrator for help.