Isn't that still "acqui-hiring" according to common usage of the term?
Sometimes people use the term to mean that the buyer only wants some/all of the employees and will abandon or shut down the acquired company's product, which presumably isn't the case here.
But more often I see "acqui-hire" used to refer to any acquisition where the expertise of the acquired company are the main reason to the acquisition (rather than, say, an existing revenue stream), and the buyer intends to keep the existing team dynamics.
Acquihiring usually means that the product the team are working on will be ended and the team members will be set to work on other aspects of the existing company.
That is part of the definition given in the first paragraph of the Wikipedia article, but I think it’s a blurry line when the acquired company is essentially synonymous with a single open source project and the buyer wants the team of experts to continue developing that open source project.
The team is continuing to develop the open source project that was synonymous with the company, but they're explicitly no longer going to try to monetize it. I think that squarely counts as an acquihire according to common usage.