The ornamental design for packaging for headphones, as shown and described.
FIG. 1 is a perspective view of packaging for headphones showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
In FIGS. 1-7, grayscale shading illustrates contour.
In FIGS. 1-7, the dashed broken lines illustrate structure or features which form no part of the claimed design and the dot-dash broken lines illustrate boundaries which form no part of the claimed design.