In case there was any doubt about Twitter’s intentions in cutting off the developers of third-party apps, the company has quietly updated its developer agreement to make clear that app makers are no longer permitted to create their own clients.The “restrictions” section of Twitter’s developer agreement was updated Thursday with a clause banning “use or access the Licensed Materials to create or attempt to create a substitute or similar service or product to the Twitter Applications.” The addition is the only substantive change to the 5,000-word agreement.The change confirms what the makers of many popular Twitter clients have suspected in recent days: that third-party Twitter services are no longer permitted under Elon Musk’s leadership.Twitter previously said it was “enforcing long-standing API rules,” but hadn’t cited which rules developers were violating. The company no longer has a communications team, and most members working on its developer pl