Score: 1.00 is the value of one pawn (in a balanced endgame). Positive values are better for white.
PV: Principal Variation, the series of moves the engine thinks is the best.
Thick red line: Marks the best move (in the view of the engine). Multiple chained arrows
means that the PV starts with multiple successive moves with the same piece, ie., the engine thinks
that the piece will execute a maneuver.
Thin red lines: Other good moves, maximum two. Note that even though these are also
quality checked, these are less thoroughly analyzed by the engine,
and should be taken with a grain of salt.
Thick blue line: Marks the best response move. Note that this is only rarely shown,
since usually, the best response move depends on what the first move is. A typical case is when the current move
is forced or nearly so.