An assembly of a plug connector part includes: a holding frame having a frame opening for receiving a plurality of modular contact inserts on a plurality of plug-in spaces arranged alongside one another along a width direction; and at least one modular contact insert insertable into the frame opening at at least one plug-in space, an arrangement of plug openings for connecting electrical conductors being disposed on the at least one modular contact insert. The at least one modular contact insert has an arrangement of connection spaces that are assigned to the plug openings and to which at least one functional element is attachable to electrically connect two plug openings to one another.