As the trial date nears in the high-stakes battle between Uber Technologies Inc. and Google Inc. driverless car unit Waymo, the two giants are disputing whether Uber chief legal officer Salle Yooshould be made available.

Yoo, who recently announced she’s leaving Uber, has information that is “central” to Waymo’s case, according to court filings.

In a Sept. 21 filing, Waymo indicated it plans to call on Yoo to “provide non-cumulative testimony regarding the Uber-Otto acquisition” and to testify about everything from the ride-hailing company’s alleged misappropriation of trade secrets to the due diligence process ahead of the 2016 acquisition.

Also on Waymo’s witness list is Arturo González, one of Uber’s lead lawyers at Morrison & Foerster, and Uber deputy general counsel Angela Padilla, who along with testifying on a number of the same issues as Yoo, would also be asked to provide information on self-driving car engineer Anthony Levandowski’s employment at Uber and certain facts surrounding his termination.

Uber returned fire in a Sept. 24 motion, arguing that there is no need for either Yoo or González to testify. “To the contrary, there is ample good cause for the Court to prohibit Waymo from calling these individuals to testify at deposition or at trial.”

In insisting that the court should issue a protective order prohibiting Yoo’s deposition, Uber alleged that Waymo can’t identify why her testimony is crucial to case preparation; what testimony she would provide that “could not be obtained by questioning any of the five other attorneys it will be deposing”; or any nonprivileged facts that she could testify on. Corporate Counsel reached out to both Waymo and Uber seeking comment. Uber declined the request.

From there, through a number of subsequent filings, both Waymo and Uber have continued to make their respective cases.

Waymo, in explaining why Yoo should be made available for deposition and to testify at trial, argued in a Sept. 25 filing that documents only recently given to Waymo show that Yoo was heavily involved in the due diligence process. The resulting report from this process, Waymo has claimed, may prove Uber knowingly acquired stolen intellectual property. The filing also notes that Yoo participated in discussions around the deal with Otto and that she was in possession of the diligence questionnaire. The Google subsidiary also insists two other in-house attorneys, Andrew Glickman and Christian Lymn, should be made available for deposition. These two, the filing said, were involved in “literally hundreds of emails … on highly relevant issues[.]” Because the court document is redacted, it’s impossible to determine the exact nature of these emails, but it appears they had to do with certain negotiations and reports on Levandowski.

To address Uber’s arguments on why Yoo should not be deposed, Waymo countered that Yoo “possesses information central to Waymo’s case—among other things, her top-down view of the diligence conducted by [forensics firm Stroz Friedberg] and the impact on Uber’s decision-making process is vital to evaluating the adequacy of that diligence.” What’s more, Yoo’s status as an attorney “is irrelevant,” according to Waymo, “given that in this case, lawyers are fact witnesses with knowledge of the Uber-Otto acquisition and the diligence process.”

The back-and-forth carried on with a Sept. 26 filing in which Uber continued to assert that there is no basis for seeking to depose Yoo and added that Waymo has similarly failed to make the required showing to allow for depositions of Glickman and Lymn.

Interestingly, it seems as though depositions of others in Uber’s legal department, such as Padilla and legal director Justin Suhr, will go forward as planned, as Uber has not filed objections.