A server system transmits from an application executing on a virtual client device, through a remote physical client device, a request for a manifest. The server system receives, a manifest received by, and forwarded from, the remote physical client device. The server system determines whether the server system is authorized to modify the received manifest. In response to determining that the server system is authorized to modify the received manifest, the server system requests additional content to modify the received manifest. The server system modifies listed content in the received manifest to generate an updated manifest. The server system sends the updated manifest to the application at the server system. The application processes the updated manifest. The server system sends, to the remote physical client device, an instruction to request the additional content.