IncludeStyle option explanation


I have a question regarding ‘IncludeStyle’ for the check ‘modernize-replace-auto-ptr’:
What is the purpose of this option for the sake of the check?

It replaces the uses of the deprecated class ‘std::auto_ptr’ by ‘std::unique_ptr’ and I am wondering what influence on that has this option ‘IncludeStyle’ which decides about the style/order of headers.
It seems these two things do not have any correlation.

I am thinking if I do not set this option at all what will change in the behavior of the check?

Thank you in advance for your help.

Best regards,