From my experience that's the "final" phase of being a junior. Where you're perfectly capable of coming up with architectures, considering functional constraints and relationships to hardware. Maybe such a junior is fresh out of university, or has spent 3-5 years working programming jobs after high school. They'll have their head full of fresh strong opinions on what's good, and have had some experience with what happens when things go wrong, and maybe mistake code they don't understand or find hard to follow for bad practices.

I'd also wouldn't frown on just calling them developer. They just need a senior developer to tell them not to rewrite everything.