This settlement was not filed in court nor presided over by a judge. It's likely that it doesn't hold water legally. When the judge dismissed the case from which this settlement was derived, she said:
"Defendantsfederal agencies represented by the Department of Justice, which has an independent obligation to uphold the 'public's strong interest in knowing about the conduct of its Government and expenditure of its resources' and the 'fair administration of justice,' neither submitted any settlement documents nor filed any documents ensuring that settlement was appropriate where there was an outstanding question as to whether an actual case or controversy existed," she wrote in her dismissal.
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"There is a glaring conflict of interest with Trump being on both sides of the claim," said Whelan, a former lawyer at the Justice Department who once clerked for the late Justice Antonin Scalia. "It is outrageous that he and those answering to him would be deciding how the government responds to these extravagant claims."
https://www.vpm.org/npr-news/npr-news/2026-05-18/judge-dismisses-trumps-irs-lawsuit-paving-the-way-for-a-settlement