Under Robodebt, you remember, hundreds of thousands of people were told that they owed money to Centrelink. It turned out that the sums claimed were generated by a computer rather than through discussions between human beings based on people's actual incomes.

With the court hearing about to begin, the Commonwealth agreed to a settlement worth $1.2 billion.

Back in May, the government agreed to repay $721 million to more than 370,000 people who had been wrongly pursued for debt they didn't in fact owe.

This week's settlement included that amount plus $112 million in compensation for the trauma of being told that they owed money when, in fact, they didn't.

Robodebt, by the way, is what the scheme came to be called because of the implication that the debt figures were generated by robots. Its official title was "Online Compliance Intervention".

The legal firm Slater and Gordon defines it as "a type of legal proceeding in which one person (the plaintiff or applicant) brings a claim on behalf of a wider group of people who have been affected in a similar way, or by the same conduct.

"By grouping claims together and pursuing them collectively, the overall value of the claim goes up, while the cost to each member goes down."

In other words, a small number of aggrieved people are chosen - or put themselves forward - to represent the whole group. These are called "representative plaintiffs". There have to be at least seven of them.

The court accepts that the small group represents the much bigger group and any victory or defeat for the small group is accepted for the bigger group.

In the Robodebt case, few if any of the aggrieved people could afford lawyers. They were or had been, by definition, on social security.

So they banded together to be represented by the legal firm Gordon Legal.

For the claimants, there were no direct legal fees. If they had lost, Gordon Legal would not have charged them under a "no win, no fee" arrangement.

Gordon Legal spelt out how a successful claim would be paid for: "We will run your case for you without accepting payment until a successful outcome is reached. Once the case is successful, the legal fee is deducted from your settlement."

As Gordon Legal explained to the claimants: "The Court will determine how much in legal costs can be deducted to ensure that those costs are fair and reasonable.

"After legal costs are deducted from the total settlement amount paid by the Commonwealth under the Settlement Distribution Scheme, the balance of that sum will be available for the payment of settlement payments to eligible Group Members."

The settlement has to be approved by the federal court (which should be a formality) and then assessments made of who is entitled to what by the end of the year.

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The weight of being pursued for money they don't have is lifted. The government also agreed not to pursue claims for $398 million in alleged debts which it had previously said were owed.

And there is the compensation of $112 million, largely for mental anguish - when you have no money or little money, to be suddenly told by officialdom that you owe a lot of money is stressful.

You get a glimpse of the anguish on a victims' website: "Overpaid $34,000 in a 6month period? Has given me severe anxiety and depression. No way possible I could owe this amount let alone pay it back. They say one debt of $34,000 is from a 6 month period in 2015 where they overpaid me."

It sounds like a lot of money but when $112 million is divided among nearly 400,000 people, it amounts to an average of around $300. Some will get more, some will get less and some will get none, depending on individual circumstances, but hundreds rather than thousands is the order of magnitude.

And Gordon Legal's fees will come out of the settlement. No figure has yet been put on that.

It does not.

One of the terms of the settlement was that, as Gordon Legal put it, "the Commonwealth has not admitted that it was legally liable to Group Members".

The joint statement with the government said: "Both the Applicants and their solicitors, Gordon Legal, acknowledge that the Commonwealth's agreement to settle the matter is not an admission of liability by the Commonwealth, and does not reflect any acceptance by the Commonwealth of the allegations that the Commonwealth, or any of its officers, had any knowledge of unlawfulness associated with the income compliance program."

The gain of the settlement for the applicants is that they get some compensation plus the lifting of the burden of being pursued.

The gain for the government is that the legal side of the affair has ended, and without ministers being brought before a court - though the political side of it may still have traction.

It is not clear that there is any gain for tax-payers not directly involved.