Apple Inc. and Google have never been wild about discussing their arrangement over web search. At some point, they may have no choice.
The Justice Department formally unveiled its long-brewing case against Google on Oct. 20. A key focus is the deals the internet giant strikes with device makers such as Apple to ensure prominent placement of its search engine. Those deals account for a large portion of the traffic-acquisition costs paid out by parent company Alphabet Inc., which now total more than $30 billion a year and have…