The DF12NB(3.0)-10DP-0.5V(51): It uses outer shroud contacts that guide the mating receptacle into alignment and protect the pins during assembly.
Board footprint and stack height
The 0.50 mm pitch means the landing pattern is dense — typical for a compact handheld or module interconnect. The 10 positions in two rows give a 5-by-2 layout, which keeps the connector body short along the board edge. The 3 mm mated stack height is the number to design to: it sets the clearance between the two PCBs when the header is paired with the matching receptacle DF12NB(3.0)-10DS-0.5V(51), which has a 2.20 mm height above board and the same 0.50 mm pitch and 10-position count.