The App URI in the ThingWorx Remote Thing Tunnel configuration specifies the endpoint of the specified tunnel. The default value (/Thingworx/tunnel/vnc.jsp) will point to the built in ThingWorx VNC client that can be downloaded through the Remote Access Widget in a Mashup to provide VNC remote desktop access. Leaving the App URI blank will result in the Tunnel being connected to the listen port on the users machine as specified in the Remote Access Widget. In this case the user must supply the application client (e.g. an ssh client) in order to connect to the tunnel endpoint.
In the marketplace there is also an SSH Extension, where one can use SSH from the platform, possibly together with the Terminal widget in the same extension. This works easy for connecting from the Thingworx Server to SSH servers in the same network. But do you know how to configure things to use the Terminal Widget and SSHServer Template to issue SSH commands from a mashup over a tunnel to an Edge Device ? Using the Remote Access Widget requires you to connect an SSH client like PuTTY to the listen port of the Java application launched by the Remote Access widget. But it would be very nice if we could use the SSH Extension and Terminal Widget to send SSH commands to the Edge Device from a mashup. Because if we use the built-in VNC client this also manipulates the visible UI on the Edge Device (e.g. a HMI), but with SSH we could manipulate the edge device without noticable visual effects.