tl;dr: Wikipedia's volunteer WikiProject AI Cleanup, launched in 2023, uses pattern recognition and AI-detection tools like Pangram to identify machine-generated content, which recently accounted for 15-20% of new articles and drafts. Beyond obvious tells like "stands as a testament," editors now hunt subtler structural patterns and fabricated citations, while deploying AI-powered source verifiers to fight back. Founding member Ellia Lebleu argues Wikipedia's human-written status has become core to its identity—both as "the last good place on the internet" and as valuable uncontaminated training data for AI companies.