The ornamental design for a plug accessory for a robotic device, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a plug accessory for a robotic device showing our new design.
FIG. 2 is a right perspective view of the plug accessory for a robotic device of FIG. 1.
FIG. 3 is a left perspective view of the plug accessory for a robotic device of FIG. 1.
FIG. 4 is a rear view of the plug accessory for a robotic device of FIG. 1.
FIG. 5 is a top perspective view of the plug accessory for a robotic device of FIG. 1; and,
FIG. 6 is a bottom perspective of the plug accessory for a robotic device of FIG. 1.
The plug accessory for a robotic device in FIGS. 1-6 includes broken lines depicting environmental or unclaimed portions of the plug accessory for a robotic device that form no part of the claimed design.