Design packages are used to group related Design Model elements together for organizational purposes, and often for
configuration management. Unlike the Artifact: Design Subsystem, a design package does not offer a formal
interface, though it may expose some of its contents (marked as 'public') which offer behavior. Design packages should
be used primarily as a model organizational tool, to group related things together; if behavioral semantics are needed,
use Design Subsystems.
A design package and its contents are the responsibility of a single Role: Designer.
Elements within the package may be dependent on the elements contained by other packages; this gives rise to
dependencies between packages. Package dependencies can be used as a tool to analyze the resiliency of the design
model: a model with cross-dependent packages is less resilient to change.