On macOS there is Dash -
https://kapeli.com/dash which can download and make easily searchable many documentations as well as StackOverflow answers. I have been using it sparingly, but for coding without an internet connection it seems ideal
I was thinking one would need to download offline copies of the most immediate tools documents but I guess I was hoping for some tried and true articles or techniques (read: silver bullet) and not have to download the whole internet and cross my fingers that I got everything I needed :)