If you're talking about a major extended outage, I would worry about having books to read, food to eat, other humans to interact with, music to listen to, and a way to exercise or at least move around outside. As a hacker you will also want some minimal low-powered computer to mess around with, because it will calm you down. Oh and a multi-band radio that also does short-wave and is crank-powered so you can keep up on the apocalypse!

Remember that if an Internet outage extends for long enough (days?) in most of Europe then parts of your society will start to fall apart and lots of people will be completely freaking out, especially in the cities. (If it's a part of Europe that had wars fairly recently, people will probably not freak out as much.)

Thus your goal is to stay physically and mentally healthy. As a thought exercise, imagine going a week with no Internet, no mobile phone, and a lot of chaos on the streets: stores and gas stations mostly closed, possibly looting, etc. How exactly would you get through that?

I guess that's the prepper version.

The "half-day internet outages and I want to keep working" version is just have lots of documentation downloaded, plenty of source code too, and don't forget to take breaks: restoring your ability to concentrate is itself a work task.