I'm not exactly certain what this is called or what the precise purpose is,
but it is an assembly of extra shingles which are attached to the hatch via
a hinge and "float" over the shingles of the cabin's exterior.
This view shows the under side of the shingles, shows them "float" over the
cabin's exterior, and demonstrates that they appear to slide over the
spacecraft's exterior via some sort of sliding pin.
Also visible, near the bottom of the picture, is one of the spacecraft's umbilicals to the adapter section