Internal references surface for Google Gemini 4 Argon, alongside reported Carbon coding claims

On October 9, TestingCatalog said hidden references to Gemini 4 Argon had appeared in Antigravity with low, medium and high reasoning-effort settings. It also said Gemini's web interface showed those settings across models. TestingCatalog cited Business Insider as reporting that Google employees were testing a Gemini 4 checkpoint called Carbon internally and that its coding performance was at the Opus 5.5 level.