[[!comment format=mdwn username="joey" subject="""comment 3""" date="2015-03-30T23:26:38Z" content=""" As to a mixed unstable/experimental machine, such a machine has a Property of having somepackage installed from experimental. One way to represent that is by defining a property: installedFromExperimental :: [Package] -> Property NoInfo installedFromExperimental = Apt.installed' ["-y", "-texperimental"] """]]