What is aptitude's extended state information

Question

I have both apt-get and aptitude installed on my system. When I am performing any operation using aptitude, I see Reading extended state information and Writing extended state information. These messages are not present with apt-get. What state information is aptitude reading that apt-get is not?

Answer 1

I believe the extended state information is stored in /var/lib/apt/extended_states. Looking at the file on my machine, it stores the architecture for each installed package and whether or not those packages were installed manually or automatically (i.e. as a dependency of another package).