If you're thinking about a cube decision before rolling you can press the same Hint button in the toolbar, as you pressed when you wanted checker play hint. The hint window will again appear, but this time it will look a bit different and it will show a hint of the correct cube decision.
The cube hint window
The first lines is the window dialog shows the evaluation depth, and the cubeless equity with the evaluated probabilities. This equity is compensated for the match score. The cubeless equity for a money game, where the the calculation of equity is not compensated for match score, is also reported.
Next follow three lines with cubeful equities. In figure above, the cubeful equity for the player on roll for not doubling at this turn, is +0.123. The equity for a double and the opponent passing is (of course) +1.000, since the player then will win one point. (The number is normalized to cube value of one, so even if it is a redouble to 4 or 8 or higher, the cubeful equity for double/pass is still +1.000 for the doubler.) The third number in figure above is the cubeful equity for the player doubling and the opponent accepting the double. The different option will be listed in order with the best option highest. The number right to the listed equities is the differences from the cube decision considered best.
The last line states the best considered cube action. In the figure above, GNU Backgammon considers the best cube action to be No double, take. When percentage number right to the proper cube action, is a number which indicates the bluff potential. It is the necessary percentage chance you think you can bluff your opponent into passing the cube to make the double theoretically correct. This number is only available when the position is considered No double, take or Too good to double, pass.