Padding (6)
I believe the answer is:
filler
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">padding</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for filler that I've seen before include "Stuffing, say" , "Something put into gap" , "A makeweight" , "Something used in cracks and cavities" , "Wall repair paste" .)