Questions about guess_mode and control_scales

[Tonsty]

The first question is what is the purpose for users of using guess_mode.

The second question is about the code related to guess_mode.
In the main code, setting guess_mode=True will set un_cond["c_concat"]=None, and generate increasing control_scales from 0.0001 to 0.01 up to down.

https://github.com/lllyasviel/ControlNet/blob/main/gradio_canny2image.py#L46
https://github.com/lllyasviel/ControlNet/blob/main/gradio_canny2image.py#L52C3-L52C4

What effect will be introduced by such settings?