The Trustee's Report of No Distribution, or NDR, lets the court and all interested parties know that no money will be paid to creditors. If a NDR is filed, the court will close the bankruptcy case shortly after the discharge has been entered.
The typical NDR beings like this:
I, TRUSTEE NAME, having been appointed trustee of the estate of the above-named debtor(s), report that I have neither received any property nor paid any money on account of this estate; that I have made a diligent inquiry into the financial affairs of the debtor(s) and the location of the property belonging to the estate; and that there is no property available for distribution from the estate over and above that exempted by law. Pursuant to Fed R Bank P 5009, I hereby certify that the estate of the above-named debtor(s) has been fully administered. I request that I be discharged from any further duties as trustee.
Then it provides some case specific information from your schedules, like the amount of debt and value of assets.
This report can be filed either before or after your discharge is entered.
If the trustee determines that you have nonexempt assets, they will not file a NDR. Instead, they'll file a notice to give creditors a deadline to file a proof of claim in your case. More on that here.