[dddw]

Zeal is a good offline code docset reader for linux and windows (but not mac!)

https://zealdocs.org/

The docsets come from Dash, which is very nice since that is payware. So here apple users pay for non-apple users it seems :)

[abathur]

Use Dash on mac, Zeal on NixOS.

I see it as a no-brainer for anyone who has more code to write than time to write it. I can't always solve a problem in Dash, but it enables me to work for hours at a time with wifi off. This is even more important for productivity when there is wifi available. Only downside that I know I'm reducing my chance of stumbling on Google Foobar trigger terms :)