Box tops (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">box tops</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lids that I've seen before include "Eye covers" , "Movable tops or covers" , "Covers for opening and closing" .)