If you use a service like GitHub you can make it private but be aware that the Info is still readable by the service provider. Not in a sense that they are gonna steal your idea (unless you invented a way to make good) but something like secrets passwords etc in your code.

I'd go for Codeberg, it's free as in free speech and beer and is an open source project based on gitea. They are working at a federation protocol to make coop doable but without the need for a centralized provider v