Gemini 3.5 Flash — default globally, Hassabis departure, 1B users milestone

Gemini 3.5 Flash now default globally. Demis Hassabis steps down as CEO of Google DeepMind. Gemini reaches 1B monthly active users and 1B Gemma downloads. Gemini 3.7 Flash reportedly in prep amid Pro delays. Google Assistant shutdown confirmed for September 4. Gemini leaked private game character names from a Google Doc.