There is no possibility to select default web camera at GNOME settings, but we can easily run into an environment with multiple cameras (integrated and the external one). As a result we can only select web camera if certain application allows us to do so via menu provided by the same application. This could be a problem, because not all applications do so - for example Firefox automatically selects first available camera on the system.
This project aims to find suitable way for adding this functionality at GNOME level. For example via contribution to Tweaks tool (formerly known as a Gnome Tweak Tool) or other tool if necessary.
This project is one of its kind!