mostlyVerifiedNodes

true if at least two-thirds of the bucket's nodes are verified. Port of bool mostly_verified_nodes(bucket_t const&):

if (num_verified == 0 && b.size() > 0) return false;
return num_verified >= b.size() * 2 / 3;

A bucket with at least one node but no verified node short-circuits to false; an empty bucket returns true (0 >= 0), exactly as upstream.