Index: Order of preference of moves. Trades off between multiple considerations (e.g. win% vs score vs uncertainty vs prior). Other orderings may be better depending on your goal. For example if you care only about likely win-loss-draw optimality and not score, ignore this ordering and pick based on the appropriate metrics directly.
Black Win%: Minimax of MCTS winrate from Black's perspective.
Black Score: Minimax of sharpened MCTS score from Black's perspective.
Win% Uncertainty: Measure of uncertainty in Win%. Does NOT correspond to any standard well-defined statistical metric, this is purely a heuristic indicator. Browse the book to get a feel for its scaling and what it means.
Score Uncertainty: Measure of uncertainty in Score. Does NOT correspond to any standard well-defined statistical metric, this is purely a heuristic indicator. Browse the book to get a feel for its scaling and what it means.
Prior%: Raw policy prior of neural net
Visits: Total number of visits, multi-counting transpositions (i.e., number of visits to produce this book if there were no transposition handling).