Border above window (6)
I believe the answer is:
pelmet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">border above window</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for pelmet that I've seen before include "Valance board" , "Fringe over a curtain rail" , "Ornamental strip to conceal curtain-rail" , "Valance, fringe" , "Temple (anag)" .)