> When you have to go in to your next standup and explain what your code does to your boss, and what you've done since the last meeting, what do you say?

You say the same thing to your boss as if you were a lead or manager reporting on a project that your junior and mid-level devs are working on. "What" is the easy part to explain; "how" is the details that your manager doesn't need to hear about if you're doing your job properly.