[jolmg]

> Debugging requires an extremely thorough understanding of the project

That's precisely why it's great for a starting point. It's work that mostly consists of research of the current code, to look for inconsistencies that cause a well-defined misbehavior. It involves writing little code and therefore involves little decision-making if any, so you avoid the newcomer making changes or adding stuff that, in ways, may be inconsistent with how things are done in the project.