Five notes covering outcome-sampling target correctness, package architecture, v0 feature-parity vs legacy, opponent-policy network divergence, and regret-matching fallback audit. Four are derived from archive sources (cited via Source: lines); outcome-sampling-target is a fresh write-up and serves as the style template. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>