A ton of things in our societies work according to anarchist principles. You also have to remember that a lot of those things are still within the existing capitalist system which exerts its own pressure to the people behind them and regularly corrupts good initiatives by either rewarding/promoting those with sociopathic behaviours within them or by exerting coercive force through threat of homelessness or starvation.
That is to say, nothing of these can be seen as an example of what Anarchism would look like if it wasn’t for capitalism. It’s all colored by our struggle against the system.
The great part about the GNU Public License (and similar) is that they’ve had a philosophical/ideological bent toward resisting that corruption. You can use the software, but you have to share the code with the people (individuals) who are actually using it. If you change it, those changes have to go to people who are using the changed software. You’re not allowed to grab other people’s work and proprietary-ize it.
It’s not perfect and corporations are constantly looking for new and innovative ways to corrupt it, but it works pretty well tbh. There aren’t a lot of things that can stop the relentless crush of capitalism at all, but open source software has been pretty successful in my opinion.
