I don't really draw much distinction between debugging and writing code. You really can't do one very effectively without the other imo

But you're right. The better indication of capability is debugging skill than writing skill.

It's kind of the same distinction between backups and restores, wherein the restores are what's important, but they're impossible without the backups to restore from.

One of the first things I do in any new-to-me project is set breakpoints in the integration tests and start stepping through the code so that I can establish some mental context. However, if there aren't integration tests, I begin writing them so that I can walk around with my debugger.