Apple senior vice president of services Eddy Cue is set to testify at the US v. Google antitrust trial on Tuesday, as the trial enters its third week. Cue’s presence, which Apple fought to avoid, underscores Apple’s importance to the Justice Department’s case against Google — which alleges that the company’s juggernaut search engine violates antitrust law. News of Cue’s scheduling was posted by Bloomberg’s Leah Nylen and Big Tech on Trial on X, formerly Twitter.

Cue will be the second Apple executive to testify, following Apple AI head (and former Google executive) John Giannandrea on Thursday and Friday. Much of Giannandrea’s testimony, however, took place under wraps in a closed courtroom. It’s unknown how much of Cue’s testimony will be open to the public or what precisely he’ll be asked. But Apple occupies a substantial role in the Justice Department’s arguments thanks to a multibillion-dollar deal that makes Google the default search engine on Safari. The Justice Department claims that Google’s agreement has kept Apple out of the search engine business, depriving users of more competition in the space while squeezing out smaller engines like DuckDuckGo, whose CEO also testified in the trial last week.

In roughly 15 minutes of public testimony, Giannandrea suggested that Apple’s browser didn’t favor Google as much as the Justice Department claimed — at least, as of last week. He noted that the newly announced iOS 17 includes a setting for selecting a second search engine besides Google, letting users pick between Yahoo, Bing, DuckDuckGo, and Ecosia. That makes switching between engines potentially easier.

Google has argued that its search engine’s quality — not its deals with Apple, Mozilla, and a variety of Android phone makers and wireless carriers — is responsible for its dominance. By comparison, it points to the default placement of Microsoft’s Bing on the Windows operating system, something that hasn’t given Bing a significant boost in the market.

But Google pays a handsome sum for prime placement in both the Apple and Android ecosystems; the Justice Department has referred to a number “over $10 billion” paid to Apple annually, although the exact price remains unknown. And other search engine makers argue it’s nearly impossible to build a loyal following that could rival it. “If you switch some of these defaults eventually you’re just going to be switched back to Google if you do nothing,” complained DuckDuckGo CEO Gabriel Weinberg in testimony.

Weinberg said that DuckDuckGo made a “quixotic” but fruitless effort to have its privacy-focused search engine implemented in browsers’ incognito mode and was stymied by the Google deals. Google, for its part, noted that DuckDuckGo has failed to get a boost from European laws that require users to pick a search engine — although Weinberg countered by claiming the choice screens were designed poorly.

Beyond the arguments made in court over Google’s search dominance, the US v. Google trial has been marked by a high level of secrecy around the company’s economic dealings. Judge Amit Mehta stated before the trial that he planned to be “conservative” with allowing potentially sensitive details to reach the public, saying, “I am not anyone that understands the industry and the markets in the way that you do, and so I take seriously when companies are telling me that if this gets disclosed, it’s going to cause competitive harm.” Mehta expressed displeasure after the Justice Department posted online copies of some exhibits seen in public court sessions, leading the department to take the documents offline while negotiating an agreement with Google to continue posting them. A resolution to that dispute was expected last week but never reached — although it’s possible we’ll see news on that front Tuesday alongside Cue.