Minor contribution to software publication: To coauthor or not to coauthor? I've been invited to be a coauthor on a software publication for an open source program where I contributed a minor bugfix.

My contribution was small, and I certainly wouldn't have been offended if I hadn't been included in the author list. But they've chosen to invite all contributors, and I'm trying to figure out whether I should accept.

On one hand, I could do with a bump to my paper count (post-doc looking for TT), and this is a project I'm proud to have contributed to. (I've joked that in code-multiplied-by-computers, my 2-line contribution to this takes more drive space in the world than my 10000-line domain-specific program).

On the other hand, I wouldn't have invited me as a coauthor. Also, I feel weird that a paper with such a minor contribution may end up near the top of my most-cited, and I'm not sure how that will appear to the job market.

Is there a downside to joining the author list for such a minor contribution?

Is it unethical to benefit from someone else's bar for coauthorship being much lower than mine?

(Looking at other invited coauthors, I see some people with similar contributions going either way; yes or no.)
Imagine the following scenario from the point of view of the main authors. They have been working on a piece of software of which they're proud, and they're writing a paper about it. They were happy with contributions from all kinds of others. It costs them literally nothing to add those others as co-authors to the paper. The resulting goodwill might strengthen the collaborative ties with those others: maybe the contributors might contribute more later. But even if they don't, and this is where the collaboration ends, the main authors have lost nothing by adding more co-authors.

Wolfgang's comment may be spot on: they may be trying to convince you to be part of a larger, longer collaboration. If you would like to be part of that, and if you are confident about the quality of the paper as a whole, I would accept. After all, they are happy to have you in the author list.