Tags (6)
I believe the answer is:
labels
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tags</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know this)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for labels that I've seen before include "tags,brands" , "'Trade names, of designers say (6)'" , "Present tags" , "Appends a category to something or someone" , "Tags; classifies" .)