At least ASF "gitbox" support a "double-master-setup":
Apache GitBox is not exactly a comfortable solution. I submitted a few patches to Maven, and while submitting the patch per se was quite easy and convenient (just a GitHub pull request, nothing specific), all the series of notifications that go on the PR and Jira becomes extremely confusing for external contributors, at the point that it's never certain how to react, or even to know whether the patch was actually merged.
So IMO, it's not the example we should follow.
It just seems like the website is basically the only repo we cannot move easily because of current deployment.
I suggest we pick another repo we'd like to move. For examples eclipse.platform.common, which contain documentation and thus is more likely to be interested to contribute to via GitHub edit link.
However, as mentioned on the wiki page, it's probably too early as the Signed-Off-By requirement currently prevents from proper adoption of the standard GitHub workflows.
