Single Comment

No engine I know of prunes in the root, in any iteration. They might reduce
the depth of poor moves compared to that of the best move by one ply, but
they will be searched in every iteration except a very early one (where
they were classified as poor) to a larger depth then they were ever
searched before. So at any time their score can recover, and if it does,
they are re-searched within the same iteration at the un-reduced depth.

This is absolutely standard, and also how Joker80 works. Selective search,
in engines that do it, is applied only very deep in the tree. Never close
to the root.