As a hypothetical employer of said hypothetical developer, I wouldn't want them to dive straight into the code; I'd want them to demonstrate an understanding of the business and technical problem we face internally, develop some ideas (preferably ones that generalize to other users of your software), and discuss those potential solutions with you.

The ideal goal would be to have someone on my own staff who understands and can improve the project's codebase, with your blessing, and who contributes towards the resilience of your project by way of adding numbers (and I'd be happy if they respond to Q&A, within reason, as part of your community, because it's part of my business' dependencies).