Looks for the best moment to wake you up for a great morning.
Waking up in light sleep feels natural - like on a weekend, without any alarm. In contrast, deep sleep wake up (which is common with ordinary alarm clocks) leads to an unpleasant experience accompanied with feeling of tiredness, sleepiness, disorientation.
This is a companion discussion topic for the original entry at https://docs.sleep.urbandroid.org/sleep/smart_wake_up.html