I was wondering what's the purpose of .viminfo and .netrwhist files?
You can see that here:
If you exit Vim and later start it again, you would normally lose a lot of information. The viminfo file can be used to remember that information, which enables you to continue where you left off.
The file ".netrwhist" holds history when netrw (and vim) is not active.
:h <any-word>. At least half the time you'll find what you're looking for. :-)
h: netrw-Th: stackoverflow.com/questions/9850360/what-is-netrwhist