All Clear / Continue.
Signals the end of a danger (yellow) zone or the end of a contolled safety pace. Also used to signal the start of a formation lap.

Both staionary and waived, the yellow flag indicates areas of potential danger. A static display is an indication of danger, and waived requests reduced speed and preparation to stop if required. NO OVERTAKING!

Both staionary and waived, the blue flag indicates the intent of an overtake from the leader(s).
Staionary: The leaders are close.
Waived: Overtake is iminent.
REMAIN ON YOUR RACING LINE!

Rarely used, the white flag indicates a slow moving vehicle on the circuit. Whether that be a kart or emergency vehicle, the flag will be waived in the sector and stationary before.
Be sure to observe and be mindful of the possibility of emerging danger ahead.

IMMEDIATELY REDUCE YOUR SPEED!
Proceed slowly and with caution, no overtaking at all! Be prepared to follow official instructions. Obey officials at all times and under no circumstances exit your vehicle unless told to do so.