I claim the ornamental design for a sheet for packaging, as shown and described.
The sole FIGURE is a plan view of a sheet for packaging, showing my new design.
The opposite side is omitted and unornamented.
The sheet for packaging has no appreciable thickness.
The dash-dash broken lines shown in the drawings illustrate the environmental structure only and form no part of the claimed design. The dot-dash broken lines in the drawings represent boundaries which form no part of the claimed design.