The ornamental design for a packagingbox, as shown and described.
FIG. 1 is a front, top, left-side perspective view of a packaging box;
FIG. 2 is a front view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a right-side view thereof;
FIG. 5 is a left-side view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 3; and,
FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 3.
The broken lines depict environmental subject matter only and form no part of the claimed design. The dot-dash chain lines depict a boundary of the claimed subject matter and form no part of the claimed design. The shaded areas represent areas of contrasting appearance to the adjacent non-shaded areas of the packaging box.