The ornamental design for a blank for packaging, as shown and described.
FIG. 1 is a right front perspective view of a blank for packaging of the present disclosure;
FIG. 2 is a left side view of the blank for packaging of FIG. 1;
FIG. 3 is a right side view of the blank for packaging of FIG. 1;
FIG. 4 is a top view of the blank for packaging of FIG. 1;
FIG. 5 is a bottom view of the blank for packaging of FIG. 1; and,
FIG. 6 is a rear plan view of the blank for packaging of FIG. 1.
The broken lines in FIGS. 1-6 are boundary lines which define the bounds of the claimed design for illustrative purposes and form no part of the claimed design. The claimed design extends to the broken line boundaries but does not include the boundaries or the area encompassed by the boundaries.