Opensource

And here we see the self-Godwin in the wild. Masterful play, sir.

Neither the CFO nor CEO are saying that Google ought to be not broken up. They are saying that Mozilla existentially depends on Google. This is actually more of a central point in the lawsuit than you think; in the original complaint, part 6 of the background is about revenue-sharing agreements (RSAs) between Google and various other companies who would normally compete in search, browsers, and other venues. That is, nobody is disputing that:

Today, Google has RSAs with nearly every significant non-Google browser (other than those distributed by Microsoft) including Mozilla's Firefox, Opera, and UCWeb. These agreements generally require the browsers to make Google the preset default general search engine for each search access point on both their Web and mobile versions.

If Mozilla did want to petition the court, then they are welcome to file as amici, but they haven't! Nor have any court filings included a reference to the CFO's testimony so far, although to be fair the testimony isn't yet available to read. There is no evidence that Mozilla will stand in the way of whatever the court decides to do with Google. Rather, in their post, the CEO is asking lawmakers to figure out some way to ensure that the browser market remains competitive:

Mozilla calls on regulators and policymakers to recognize the vital role of independent browsers and take action to nurture competition, innovation, and protect the public interest in the evolving digital landscape.

Courts aren't regulators or policymakers. The complaint before the court is not the same as the underlying principles of antitrust which motivated the complaint. A request to improve the future is not the same as a request to forestall the present.