Lens mount removed. Shims in the fixed rear (enlarging) group are visible, as well as the electric contacts in the lens mount. Note silver-y ring with notch retained by the brass shim. The silver ring is a mechanical relay for the aperture.
<a href="//commons.wikimedia.org/wiki/User:Phiarc" title="User:Phiarc">Phiarc</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>