How to merge two GitHub repos?

Question

This question is not about how to merge two git repos; that problem has already been discussed (keywords: "submodules", "subtree merging").

The question here is, how to merge two GitHub repos?

I wanted to preserve as many GitHub features/data from both GitHub repos as possible. Most importantly, I want to preserve issues and wikis from both GitHub repos.

How might I achieve that?

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Info:

I have just learnt that GitHub wikis are git repos themselves (summary: git://github.com/you/proj.wiki), and I have successfully pushed changes to a wiki-repo of mine.

Answer 1

Regarding issues, there is no native way to "import" them, you need to recreate them.

You have for instance a project like "github-issue-importer" which could be extended to fetch issues from one GitHub repo and import them in another.

This gist seems to import from one GitHub repo to another.