The ornamental design for a packagingbox, as shown and described.
FIG. 1 is a front perspective view of a packaging box 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;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an exploded perspective view of the packaging box, in which a tray for packaging box in broken lines is provided to illustrate an example environment.
The top and bottom portions of the packaging box are identical mirror images.
The broken lines depict environmental subject matter only and form no part of the claimed design.