TurnKey Linux virtual appliances are built almost entirely from unmodified Ubuntu binaries, it is possible for anyone to verify the integrity of the binaries that make up a virtual appliance against the original package signatures from the official Ubuntu repositories. There are minor exceptions. When required, a virtual appliance may contain a few custom packages which are updated from our cryptographically signed package repository. Full source code for all custom components is available in our code repository. Some components are also hosted on github.
In the new rPath rBuilder flash UI the “resign from appliance” button is disabled so you need to either switch to the old UI or go directly to the old project membership page