I am a junior developer of iOS and iBeacon. I don't know when and why to use the following in my development.
ESTBeaconManager recentlyUsedUUIDs recentlyCachedBeacons
These are not demonstrated in the example demos. Hope that someone can help me.
"peripheral" property is a reference to the underlying Core Bluetooth device. You won't need it in a vast majority of cases—in fact, if you don't have an idea how it could be useful to you, it probably isn't, so I wouldn't worry about it (:
"recentlyUsedUUIDs" and "recentlyCachedBeacons" are mostly for caching and performance purposes—again, nothing to usually concern yourself with at the early stages of building your app and/or experimenting with beacons.
All of these properties are documented here: