> So I can find a bug, I can fix it, but I am not allowed to tell them how exactly I did it.

Pin pointing the issue is way more than valuable than code. If you wrote a fix, you have analyzed the bug. The value is there, not in the fix. Sharing your fine analysis is the maximized contribution. Code is an optional bonus at most.

exactly. a _proposed_ code fix is a good indicator where the problem is (analysis) but more often than not the actual maintainable and sustainable solution will look different.

a code owner may choose a very different way of fixing things, even for what looks like a trivial fix.