It's all relative and obfuscated given we're trying to place software development under definitions of social thought, and similar as to how Marxism isn't about trying to place your family's store in either the bourgeois or petit-bourgeois bucket, it makes it even harder to place specific software under definitions as well. So take this as just a fun exercise!

But I guess based off my previous examples, you could say that Signal would fall under a category of more "socialized" means of production but for the profit (in this case "profit" as Signal's dealings are murkier, this is a good read on it) in the end for someone else, or "socialized" production under a capitalist system, which is still exploitation; the closest real-world example would be co-ops. While co-ops are those specific workers technically owning the means of production for that specific company, but it still being a company working within capitalism, it doesn't change anything as it's not societal.