What file is default browser in, or how does one change it? I am assuming when I know this I may also stumble onto some other default settings that the knowledge of which may help someone else...

that depends on 2 things mainly..... the desktop environments (usually KDE or Gnome, tho there are 1-3 others, plus people can just use the programs separate (kinda making there own)) (only because most newbies use desktop environments, and the fact that anyone would ask such a question with that little info has to prove they are newbie) and also what program are you trying to use when opening the web browser (this is only important if you don't use desktop environments, as the desktop environment usually have some little setting for getting it to work with everything in the environment fast

so, just to recap

1) what desktop environment do you run?

and if you don't run a DE then:

2) what program do you want to set it up for?

Your right, I am very much a newbie. Though I should have known to include a desktop environment.

I use KDE. Hopefully it has a global setting.