Where are the manifest of an asp .net web site located?

I need to find a way to configure the manifest of a website in order to change the version number or add a redirection binding of a referenced assembly on production. When it comes to windows applications its pretty easy to find the configuration file attached to the exe file and do the desired changes, but i cant seem to find it in a web site (not a web application although i think its the same there). I checked the web config but the assembly reference was not specified there. Does anyone know where to look?