Forty-niner's filing
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">forty-niner's filing</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 claim that I've seen before include "Assert; demand" , "title" , "Assert; request" , "Right; demand this" , "Formal request" .)