Ask HN: What do you consider a technical cofounder?

I am curious about what people think about how to judge who is and who is not a technical co-founder. For instance, if someone has a solid understanding of MVC and Ruby on Rails, understands version control, and how to break down features into user stories tracked on pivotal tracker (or whatever), are they technical? Especially if they are not actually writing the code? Or even let’s say that the development is maybe using React.js or Vue wrapped into the rails project, and they have little idea of how to actually write that code. Are they still qualified as a technical co-founder? Another way to ask it, if something breaks but they have to rely on other team members to fix it, are they the a technical co-founder?

I ask because tech stacks often change and often change underneath the feet of a founding team. And at some point, and maybe I’m wrong, no one person can fix all things.

So is appreciation for how to do development the qualification to honestly say you’re a technical co-founder, or should you only say that if you know the entire stack of your product to a high degree of individual competency? Asking for a friend ;-)