Outside this community: someone who programs computers.

In this community: no one has any fucking idea how to answer that.

What's a humor?

Someone else wrote some code, and he reviewed it and approved it, and merged it into the codebase.

Oh I would hope not, it's good practice to not let the person writing the code merge it in, to get a fresh pair of eyes on the code before it goes in.

Though in a way you could say he "fixed a bug" by merging a bugfix written by somebody else, but that feels like a failure of attribution.