When upgrading an item with a passive effect into another item, is this passive still included in the upgraded item, even when not specified? It seems counter-intuitive that it would not, but I am still unsure.
For example, Seeker's Armguard has a passive which grants 0.5 armour and ability power upon killing a unit, stacking up to 30 times. Seeker's Armguard then builds into Zhonya's Hourglass, which does not list the same passive effect (it only has a unique active: stasis). Am I to assume it does in fact include the Seeker's Armguard passive effect and it is just hidden, or that it does not?