In some projects, there are so-called dummy devices which (usually) are in the area main line. The purpose here is simply to make a Group Address visible on the area main line as well (i.e. the telegram) by assigning various Group Addresses to the corresponding Group Objects of these devices, for example for visualizations. This 'artificial' assignment of Group Addresses to Group Objects causes the filter tables of the couplers to be adapted accordingly (opened).
Dummy devices are not a good choice for reaching this objective (see Dynamic Folders). It would be more correct to manually enable individual Group Addresses in the filter tables.