Hero Siege keys

The rate is the base figure the in-game journal prints: the one-in-N chance the client stores for that item dropping anywhere, before Magic Find and before any zone or buff bonus. Where a place is named, the client also stores a better rate for that item in that place, listed on the place pages.

An item with no rate has no base rate in the data recovered so far, which usually means something hands it over directly rather than dropping it.