They are obviously still only thinking about this building. Before going ahead with construction, the client has to approve the materials used. Of major aesthetic importance are the cladding panels, and clients want to see actual samples, specimens, not just diagrams or photos. This often involves building a section of wall, including windows, to show how everything fits together and what the colour, texture, etc. look like in the light of day. So they are going to see a new "presentation" of the sample (or samples), together with elevation drawings, presumably to see the "calepinage" of the panels (how they are set out on the wall, in relation to windows etc (one tries to have multiples of panel width matching multiples of window width, to avoid ugly joints, etc.).

Témoin - cf appartement témoin = model/show/sample apartment.

Similar for OTIS. OTIS won't build a sample lift for them, but CAN take the client to see equivalent lifts on other projects.