These are package components with a namespace prefix. When you enable a developer/isv org to create packages you should pick a namespace. This namespace will be specific to all your custom components (but also custom fields etc) and they will be known as such in any org that deploys your package.
You still define and build components the way you're used to:
In a visualforce pages you can no longer use the
c: notaction but have to use your namespace prefix:
So, these components work just the same way as the ones you're building yourself, but they are designed to also work in other orgs where they should have a separated name from anything else already there.