Contributing to a software project vs double blind review We have added a new experimental feature to an existing software project (e.g. on GitHub), and we would like to publish a paper about it. However, we want to publish it in a venue which uses double-blind review. What is the correct method of anonymization in this case?
I see several ways which all seem to have major issues:

cite the project, clearly state which part is our contribution,
include it as a supplementary material anonymizing our contribution
-&gt; the issue here is that the reviewers will either already know the software project (and then likely know that such a feature has been
added), or they will not know about it, look at it, and likely find out
that this feature has been added, breaking anonymity. This seems to
be the best solution to me, however, since the rules for anonymity
tend to be quite strict, we are not sure whether this would be
acceptable.

anonymize the whole project -&gt; this is basically
(self)-plagiarism (especially if there are  already papers published
about the original project).

do not include the implementation, only the results -&gt; this
makes it less reproducible, and more difficult for the referees to
review. Also it might be still good to cite the original project, with the drawbacks of (1).


This would not be a problem for a normal peer review (not double blind), or if the project is completely original (there are several questions on this site about this case).
I think you should submit the article to the venue of your choice, with a note to the editor/administrator explaining that although your names will not be on the paper when it goes out for review, a reviewer in your field could easily deduce your identity from the references to public software.
In double blind refereeing the onus on blindess is shared. You don't say who you are, and the referees don't try to find out. The fact that they might be able to identify you from something in your work is not necessarily your problem.