For a better understanding of the further material, read the following descriptions.
A physical working unit that consists of model, model visualizations (diagrams, tables, matrices, etc.), configuration data and references to other elements residing in used projects.
Used project (up to 18.0 – Module)
A project having one or more shared packages. Used projects are created for the purpose of decomposing projects into parts in order to manage each part separately and/or reuse those parts in other projects. Used project is a role that one project plays in the composition of another project. It is not a type of project. Each used project can be opened and modified separately.