I am using Ubuntu and when I click on a program to download Firefox asks me "What should firefox do with this file?" And in the "Open with" I would like to find a program "Package installer". The problem is - I don't know where to look for. Where is the program stored (I installed it using Ubuntu Software Center)
If you installed the package with the Ubuntu package manager (apt, synaptic, dpkg or similar), you can get information about the installed package with
dpkg -L <package_name>