Misc. questions about some selections

I believe these are 'Default' selections.

Under 'Windows' - IE- " what is Index.dat files?"

Under 'Applications' - Windows - MS Management Console - "is that referring to Event Viewer?"

Also under Apps - it still lists Thunderbird which I uninstalled long ago. ?

- lists 2 versions of Foxit Reader. ?

- lists 2 versions of Avast. ?

- lists 2 programs that I've never used, came Pre-installed when I bought PC. ?