Blueprint detail (4)
I believe the answer is:
spec
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">blueprint detail</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 spec that I've seen before include "Detailed design (colloq.)" , "Description of requirements" , "Estimate" , "Awkward, clumsy" , "Bet" .)