To this point, we have only been dealing with jQuery widgets as components. While extremely powerful, jQuery widgets are not best suited for rendering robust components with complex HTML structures. The other type of JS components is what we refer to as UI/KnockoutJS components. Built on the shoulders of the KnockoutJS library, these components allow powerful templating of our data, among other things. Without getting too deep into the ins and outs of these type of components, suffice to say that the main construct we are referring to when we speak of UI/KnockoutJS components is uiComponent.
As per <MAGENTO_DIR>/module-ui/view/base/requirejs-config.js, the uiComponent maps to the Magento_Ui/js/lib/core/collection JS file. Inspecting the collection.js file, we can see that uiComponent extends uiElement, which maps to the Magento_Ui/js/lib...