TechTimes reports that a model checkpoint labeled GPT-5.6 "Kindle-Alpha" surfaced in OpenAI's Codex-related testing paths on June 3 and has since circulated in developer channels. According to early reports cited by WinCentral, the leaked build hints at a 1.5 million token context window and noticeably cleaner UI generation from minimal prompts. Multiple internal codenames — including "iris-alpha," "ember-alpha," and "beacon-alpha" — were also reportedly spotted in developer build logs, suggesting OpenAI may be testing several variants simultaneously. Polymarket traders are currently pricing 80–89% odds of a GPT-5.6 release before June 30. OpenAI has not confirmed the model exists, and all details remain unverified until an official announcement.