A clickbait-y title if ever there was one. And, yes, I clicked it ...
Sorry I actually thought that everyone knew what devdocs.io was -- definitely didn't intend to be clickbaity there!
Edited the title
Why before a flight?
It's as good a time as any?
After installation, you can use the website completely offline. You don’t even need to keep it open in a tab; just pull up devdocs.io even without internet.
This is the answer, updated the title to be way clearer