When William Leggatt was at work as a renewal energy developer a couple of summers ago, he received a bizarre email from a superfan of “Operation Mincemeat,” a British musical about a wacky World War II intelligence plot.

As the show outlines, the operation involved British spies dressing a corpse as a military officer, stuffing a briefcase with fake letters implying an imminent invasion of Sardinia, and then dumping the corpse and documents at sea to be discovered by the Nazis.

So the email contained a simple question: Was William a distant relative of Hester Leggatt, a prim secretary who appears in the musical and played a key role in the plot?

The show’s superfans, who meet in an online forum and are known as Mincefluencers, believed that Hester was involved in writing fake love letters that officials planted on the body to help make the plot believable — and that she deserved to be publicly honored. But William Leggatt had no idea what the email was talking about.

It was only when he started talking to family members who were closer to the great-aunt and, later, reading a document sent by the Mincefluencers, that he realized they were right. In the end, he recalled in a recent interview, the musical “opened a whole side to my family I’d never known.”

Since debuting in London in 2019, “Operation Mincemeat,” which opened on Broadway last week at the Golden Theater, has won plaudits for turning wartime espionage into a satirical musical. For William Leggatt and other descendants of the real life figures depicted onstage, it has also unearthed family secrets and brought newfound appreciation for their forebears.

In the musical, Hester Leggatt (Jak Malone, one of five cast members playing numerous parts) is depicted as an unemotional prude until she takes on the task of writing the love letters and sings a heart-wrenching showstopper called “Dear Bill.”

World War II aficionados had been aware that a secretary called Hester had written the romantic notes, potentially with help from others, since the journalist Ben Macintyre named her in an acclaimed 2010 history. But a slight discrepancy in the spelling of her surname meant that when the musical opened, the real Hester remained largely a mystery.

Once the Mincefluencers discovered the correct spelling, they set about finding Hester Leggatt’s descendants and eventually produced a 50-page document about her life, which even detailed a play that she performed in at school. The superfans also got MI5, Britain’s domestic security service, to confirm that a Hester Leggatt had worked for the service during the war.

William Leggatt said he never met his great-aunt, who died in 1995, and knew nothing of that background before receiving the email.

It was “pretty annoying,” he added, to find out decades after her death that she had played a role in a famous World War II plot because, he said, he would have loved to have quizzed her about it. Still, he said: “I don’t think she told even those close to her. She kept it pretty bloody secret her whole life.”

For other descendants of the Operational Mincemeat spies, the musical has led them to delve more into their family history or changed their perceptions of long-lost relatives.

Susie Pugh, a granddaughter of John Bevan, the official who approved the plot, said in an interview that attending the musical had rounded out her image of a man who died when she was 15. She had known him as an affectionate grandfather, she said, yet onstage he was “confident, strident” and ordering spies around.

Jessica Baldrian, a granddaughter of Charles Cholmondeley, another spy, said that her family had chatted regularly about him since seeing the show. She said it got some things wrong, including portraying him as a newt-obsessed nerd (the family could find no evidence of his amphibian fancying). But, she added, it was a musical: “You don’t expect it to be accurate.” Like many of the spy descendants, Baldrian traveled from Britain for the recent Broadway opening to see her grandfather portrayed on the New York stage.

One descendant has even become a Mincefluencer himself.

Saul Montagu said he had long known that his great-grandfather Ewen Montagu had masterminded the operation, not just because Montagu wrote a 1953 book about it, called “The Man Who Never Was.” The walls of the family’s home in Oxford also include numerous photographs, a painting and a caricature of Montagu, one of which was signed by Winston Churchill in gratitude for his service.

But Saul Montagu said that as a teenager he had thought little about his great-grandfather, who died in 1985.

That changed in January 2020 after a family outing to see the musical. He began delving into his great-grandfather’s life, first reading his book and then his unpublished autobiography and a handwritten diary from a year at Harvard in which he confessed to spending more time dancing and sourcing contraband liquor than studying.

As Saul Montagu’s fandom for the musical grew, he recalled, he joined the main online Mincefluencers group and answered questions about his great-grandfather.

The research, Montagu said, “humanized” his great-grandfather, making him far more than simply a cool tale to tell friends about. Now, he added, he has seen the musical 13 times, and even joked with Natasha Hodgson, the actor who plays his ancestor, about how they were “family.”

In interviews, six descendants of the characters said they loved the show, though not all were convinced that their ancestors would agree.

William Leggatt said of his great-aunt Hester, “for her contribution to finally be recognized, I’m sure she’d have been happy with that.” But if she discovered that a man was portraying her on Broadway, he said, “there’d have been some spluttering.”

A lawyer for Columbia University said Tuesday that a demand from the Trump administration for dramatic changes in student discipline had merely sped up policies the university had already been planning to enforce.

In a March 13 letter, the Trump administration said the university had failed to stop “antisemitic violence and harassment,” adding that policy changes would have to be made before the government would discuss resuming $400 million in canceled grants and contracts. Last week, the school complied with most of the government’s requests, regulating masks on campus and empowering a team of security officers to make arrests.

The lawyer’s assertion that Columbia had been planning the changes all along came during a hearing in Federal District Court in Manhattan over a request by a group of anonymous Columbia and Barnard College students that a judge bar school officials from handing over confidential disciplinary records to a congressional committee that has asked for them.

Both Columbia and the committee have contended that the students have not shown a sufficient legal basis for such an order. The judge, Arun Subramanian, made no ruling Tuesday.

The arguments in court stemmed from a request by the House Committee on Education and Workforce for disciplinary records related to several incidents, including the occupation of a university hall last spring by pro-Palestinian demonstrators, a protest of a class taught by former Secretary of State Hillary Clinton, and an art exhibition the committee said had “promoted terrorism.”

Seven anonymous students and Mahmoud Khalil, a former student and legal permanent resident who helped lead protests last year and whom the Trump administration is trying to deport, sued to keep the records private. The lawsuit said that to fully comply, Columbia would have to turn over private files of hundreds of students, faculty and staff members.

Their lawyers have argued that the House committee was trying to coerce the university into becoming the government’s proxy to chill speech critical of Israel and to suppress association, actions that the First Amendment would prohibit the government from taking.

Marshall Miller, a lawyer for Columbia, denied in court on Tuesday that the university was being coerced, saying that it was voluntarily responding to government requests.

At one point, Judge Subramanian asked Mr. Miller whether Columbia would have announced new rules last Friday without a suggestion from the executive branch that money was at stake.

“It’s a hypothetical,” Mr. Miller said.

“I don’t think it’s a hypothetical,” Judge Subramanian replied.

Mr. Miller then conferred briefly with colleagues before saying that although the new policies had been developed over many months, the Trump administration’s demand affected their “precise timing.”

Ester R. Fuchs, a Columbia professor who is the co-chair of the university’s antisemitism task force, said last week that “a lot of these are things we needed to get done and were getting done, but now we’ve gotten done more quickly.”

The provisions the school adopted were made public in an unsigned statement that many faculty members greeted with dismay, seeing an unprecedented level of deference to the Trump administration.

Among other things, Columbia banned face masks on campus for the purpose of concealing identity during disruptions and said it would adopt a formal definition of antisemitism.

The university also said it would appoint a senior vice provost to oversee the Middle Eastern, South Asian and African Studies Department, which the Trump administration had said should be placed into receivership.

Lawyers for the students said their clients could suffer harm if their disciplinary information was handed over to lawmakers allied with the Trump administration. The lawyers wrote in court papers that after Columbia provided such information to the government last year, “members of Congress or their staffers posted students’ private information on social media sites and identified students and faculty on the public record during congressional hearings,” resulting in harassment.

Mr. Miller said on Tuesday that Columbia had “anonymized” information provided to the committee.

A lawyer for the students, Amy Greer, said that students who had participated in pro-Palestinian demonstrations were “some of the most surveilled people in our country right now,” adding that several private organizations had worked to target students for their speech.

Even if Columbia removed names from information it gave the committee, the inclusion of physical descriptions and details of activity at specific times and places meant “somebody is going to recognize them,” Ms. Greer added.

Earlier in the hearing Judge Subramanian had asked a lawyer for the House committee what lawmakers might do with the student disciplinary records.

The lawyer, Todd Tatelman, replied that the identities of students might in “certain circumstances” be relevant.

“There is no intent to publicize student names?” Judge Subramanian asked.

Mr. Tatelman replied that he knew of no such plans. The judge asked next whether the committee would turn over the names of students to any “administrative agency.”

Mr. Tatelman replied that it would not be “a typical action.”

“But you cannot rule it out?” the judge asked.

“At this point,” Mr. Tatelman replied, “I cannot rule anything out.”

During his U.S. Senate confirmation hearing to become the No. 2 official at the Justice Department, Todd Blanche suggested that he had no direct knowledge of the decision to abandon a criminal corruption case against the mayor of New York City.

But in a draft letter unsealed on Tuesday, the interim U.S. attorney in Manhattan wrote that a top department official, Emil Bove III, had suggested otherwise before ordering her to seek the case’s dismissal.

The U.S. attorney, Danielle R. Sassoon, wrote that when she suggested that department officials await Mr. Blanche’s Senate confirmation so he could play a role in the decision, Mr. Bove informed her that Mr. Blanche was “on the same page,” and that “there was no need to wait.” The draft was written by Ms. Sassoon earlier this year, as she fought for the case’s survival.

The draft letter was among a cache of communications, including emails and texts, submitted under seal to a judge, Dale E. Ho, by Mr. Bove and Mr. Blanche, after his confirmation, to support their argument for dismissal of the corruption indictment against the mayor, Eric Adams. Judge Ho has yet to rule.

The draft sheds additional light on the circumstances surrounding the explosive decision by top officials in the Justice Department to halt the prosecution of Mr. Adams. The decision set off a political crisis in New York City, where the mayor immediately faced questions about his indebtedness to the Trump administration, which sought the dismissal in part so that Mr. Adams could aid its deportation agenda in New York City.

A Justice Department spokesman said in a statement that Mr. Blanche had no role in decisions at the agency before he was confirmed.

“Todd Blanche was not involved in the Department’s decision-making prior to his confirmation,” the statement said.

During the confirmation hearing, Mr. Blanche was questioned about the Justice Department’s decision making in seeking the dismissal of the Adams case.

When Senator Peter Welch, a Vermont Democrat, asked Mr. Blanche about whether the decisions in the case had been directed by officials in Washington, Mr. Blanche suggested that he had no direct knowledge.

“I have the same information you have,” he said. “It appears it was, yes, I don’t know.”

Reached for comment on Tuesday, Senator Welch said, “If this is true, it clearly indicates Blanche ‘misled’ — in plain English, lied — to the committee.”

It was not immediately clear when Ms. Sassoon drafted the letter. When it was originally filed, under seal, Mr. Bove wrote that Ms. Sassoon sent it to herself on Feb. 12. But the unsealed documents show that Ms. Sassoon sent herself an email that appeared to include the drafted letter as an attachment on Feb. 11 — the day before Mr. Blanche’s hearing.

This is a developing story and will be updated.

Emma G. Fitzsimmons contributed reporting. Susan C. Beachy contributed research.