This symbol indicates that this segment is 100% identical (i.e. an exact match) to the segment from row 2, which you have previously translated and stored in the TM.
Ta simbol pomeni, da je ta segment 100-odstotno identičen (tj. natančno ujemanje) segmentu druge vrstice, ki ste ga nedavno prevedli in shranili v pomnilnik prevodov.