It's often interesting not to only know the "future" PV agreement, but also whether the move just played was expected by an opponent (aka "ponderhit"). That could be not only opponent but also kibitzer engines.
I don't know how exactly that can be implemented (as one more arrow/pair of symbols on a board; or something in parentheses after the last move in the move list etc), but I think that's something to consider.
Maybe something like this, but I don't like that UI decision too much (in this example, SF expected Lc0 to play Nf3, but Lc0 played Qd2):
It's often interesting not to only know the "future" PV agreement, but also whether the move just played was expected by an opponent (aka "ponderhit"). That could be not only opponent but also kibitzer engines.
I don't know how exactly that can be implemented (as one more arrow/pair of symbols on a board; or something in parentheses after the last move in the move list etc), but I think that's something to consider.
Maybe something like this, but I don't like that UI decision too much (in this example, SF expected Lc0 to play Nf3, but Lc0 played Qd2):
