Why is the draft budget with a deficit puzzling?

Sometimes I don't quite understand the phrase: "Next year, we will check the draft budget with a deficit."

What does this mean? What, like, expenses exceed income?

But in fact, it is clear that such a phenomenon cannot happen. There can't be a minus of some trillions of rubles in your pocket. This means that the work on budget planning has not been completed to the end.

If expenses are planned at a certain level, and they cannot be cut, and current income is not enough to cover them, then it is obvious that this difference must be covered by something.

It would be more interesting to hear this: "Next year, a draft budget will be drawn up, in which the volume of national debt will increase by such a percentage (amount) or gold and foreign exchange reserves will be reduced by so much."

The budget cannot be implemented with a deficit - this is a common verbiage.

The question is different: no one ever says what is planned close these holes.