Not sure what the right word is, but textbook-definition communism fits - open-source code isn't really owned in practical sense.
Open source is inherently communistic because nobody owns anything. You have control over your own project, but that's where it stops. You cannot force open source maintainers to do something. This is unlike capitalism; at a standard company, your NDA forces you not to disclose secrets. In open source, there are no secrets to disclose, short of drama and private infighting. A non-compete prevents you from forking the business you work for. These are unenforceable in Cali, but the rest of the US is not so lucky.
You are bound to a paycheck that determines your fate. This is the essence of capitalism.
Contrast that with open source: people don't merely contribute because they want to. It increases their reputation. Ditto for a review system on darknet markets.
Both of these things are very unlike capitalism. So if not communism, then what? Not libertarianism. There's no ownership, and ownership is central to libertarian ideals.
I think the question as a whole doesn't really make sense, since "open source" can't be separated from the whole economies in which it is created.
(¹ communists would object that the choice is often illusory or even non-existent, but that's another issue)
Yet we insist on conflating them, and argue against the one whenever the other is mentioned, as if it's synonymous with both.
EDIT: Point being, the economic milieu one finds one's self in, is that in which one tends to be obligated to participate — especially at the lower levels of power within that model.
That is: regular folk are trapped in the system they're born into. It is not meaningful to call their participation voluntary on their part. They may have nominally more freedom within the model in capitalism, but they're, on the whole, just as obligated to participate; they are just as much grist for the mill, under either model.
The problems with the 'voluntary' nature of capitalism are best summed up by Anatole France: How noble the law, in its majestic equality, that both the rich and poor are equally prohibited from peeing in the streets, sleeping under bridges, and stealing bread!