The project and development plan becomes part of the project-specific zoning plan (Section 12(3), first sentence, of the German Building Code (BauGB)).
The plan sets forth the details of the project and the associated development measures, which the project developer commits to implementing in the implementation agreement.
Anyone may inspect the relevant documents (project and development plan, project-specific zoning plan, justification for the zoning plan, and a summary explanation of how environmental concerns and the results of public and official participation were taken into account in the zoning plan, and on the reasons why the plan was selected after weighing it against the reviewed, viable alternative planning options) are available for public inspection.

The documents are available (though not yet for all plans) on the respective municipality’s website.