Managed development areas are deployment areas that are assigned to the first stage in the global stage lifecycle, typically the DEVELOPMENT stage. You can use managed development build areas as integration build areas for source code changes done by a development team when the code is not ready for deployment to a stage such as UNIT TEST or SYSTEM TEST.
Build areas are maintained the same as all other areas. For example, if you create an item revision it is automatically deployed to all managed development areas associated with the first stage. If you deploy an item revision from the DEVELOPMENT to UNIT TEST stages, it is removed from all managed DEVELOPMENT areas.