What's the use case for changing internet_session_* settings in INI file?

[achu]

I saw bunches of internet session related varaibles available in the ini file. for example, internet_session_agent, internet_session_cache, etc.
What are the possible use cases?   

[Derek Read]

These variables affect opening XML documents over http (i.e. Web folders + Webdav) and should generally be left at their default settings.