Xbox is quietly testing what could become one of the most consequential changes to Game Pass since Microsoft split the service into new tiers last year. A new codenamed plan, “Triton,” appears to be surfacing in Microsoft’s public Game Pass backend, and early evidence suggests it would include only first-party Xbox games for now rather than the broader mix found in Essential, Premium, or Ultimate. That makes the rumor easy to dismiss as just another backend experiment, but it is more...