A question on 'example.ipynb'

[2019211753]

'Attack Pong-PPO policy with Uniform Attack with attack frequenc7 0.5. Moreover, let's suppose we don't know the agent policy is PPO and let's perform attacks on a A2C policy trained on the same environment.'
What does it mean?

[2019211753]

For example, using A2C as the victim policy instead of the targeted PPO policy to initialize the C&W attack, but attacking PPO, what is the effect? Is this to verify the transferability in black-box scenarios?Thanks a lot!