Shell of an Electronic Device

FIG. 1 is a top front perspective view of a shell of an electronic device 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. The broken lines seen in the drawings represent unclaimed portions of a shell of an electronic device and therefore form no part of the claimed design. Unshaded surfaces shown between solid and broken lines form no part of the claimed design.