The ornamental design of a dust bin viewing window for a robotic vacuum cleaner, as shown and described.
FIG. 1 is a front right perspective view of a dust bin viewing window for a robotic vacuum cleaner showing our new design;
FIG. 2 is a rear elevational view thereof; and,
FIG. 3 is a top elevational view thereof.
In FIGS. 1, 2, and 3 the broken lines showing the robotic vacuum cleaner and associated details are for illustrative purposes only and form no part of the claimed design.