SAN FRANCISCO — Lawyers and engineers occupy professional worlds which have their own distinct codes, quirks and vocabularies.

Thursday afternoon, on the fourth day of the high-profile trade secrets showdown between Waymo and Uber, the professional differences between lawyers and engineers were on stark display, particularly during the testimony of Waymo engineer Sasha Zbrozek.

Zbrozek, who managed one of Waymo's file servers central to the case, wrote emails that attorneys for both sides raised in opening statements Monday. In them, Zbrozek appeared to downplay the value of the 14,000-plus Waymo files former engineer Anthony Levandowski downloaded from the server shortly before he left Google to found a company later acquired by Uber.

“It was considered low-value enough that we had even considered hosting it off of Google infrastructure,” Zbrozek wrote in an October 2016 email to Waymo outside counsel Thomas Gorman at the firm then known as Keker & Van Nest. Zbrozek later wrote to in-house counsel at Google that it made him “uncomfortable” to think lawyers were ascribing a value to the number of files Levandowski downloaded.

Waymo attempted to defang the potentially damaging emails by calling Zbrozek and addressing them head-on. Taking the stand, Zbrozek took the peculiar step of spelling his name using the phonetic alphabet popular with ham radio operators, possibly a nod to noted ham enthusiast U.S. District Judge William Alsup, who is overseeing the case.

Under questioning from Duane Lyons of Quinn Emanuel Urquhart & Sullivan, Zbrozek explained that the server in question was designed so that anyone logging in would automatically download the entire repository of files containing Google's working designs for a driverless car. He also explained that when he made those comments about being “uncomfortable” with lawyers making a big deal about the number of files downloaded, he wasn't aware that Levandowski had apparently copied the files to an external storage device and uploaded them to his personal laptop.

Asked about his comment that the sever's contents were “low-value,” Zbrozek said that traditionally at Google, user data, software code and algorithms have been considered high value. “The hardware [at all levels] was a second class citizen,” he wrote in a later email. “Maybe opinions have changed.”

On cross-examination, Uber's lawyer, Arturo González of Morrison & Foerster, asked if anyone at Google had suggested it was a bad idea to design the server so anyone logging on would download all the files.

“Uh, no,” Zbrozek said.

“Your employer is alleging there are trade secrets in there,” González said.

Zbrozek replied that he hadn't paid attention to what was in the lawsuit.

“I don't know what a trade secret is,” Zbrozek added later, noting that he has been trying to avoid learning the legal definition.

González closed his examination by walking Zbrozek through an email he received from Google in-house lawyer Shana Stanton just a day before Waymo filed suit. Stanton wrote that Waymo wanted to be able to say the server “contains only internal confidential stuff.”

González noted that Stanton was watching in the courtroom from the front row near the jury. He then proceeded to point out that she had copied the message to litigation counsel at Quinn Emanuel, including other lawyers in the courtroom.

Zbrozek recognized Stanton after she was pointed out, but didn't recognize the Quinn Emanuel lawyers.

“I don't know where they're from,” Zbrozek said.