> - How could CI/CD be set up? (Is read-only access possible to the repo? Would Keybase work on a Jenkins box? Could a deploy server verify signatures before deploying?
You could have a deploy/CI user as a "reader" in your team. But we don't yet support hooks or anything (as that implies running arbitrary code on endhosts without their knowledge), so it would have to pull the repo.
> Could one set up mirroring to GitHub? How would this work? (I could see the signing without encryption as a value-add)
You can of course continue to use Github as a regular remote, but you'd lose all the encryption and signing unfortunately.
> - What happens in the event of a force push? Could certain users destroy history?
We do currently allow force pushes. Being able to turn that off on a repo-by-repo basis is something we'll consider in the future, definitely.
> Could protected branches eventually be added, eg only certain users can push to master?
Yes, but again, as with any "server"-side feature, this is complicated by the fact that it has to run on the client itself, and thus isn't really strictly enforceable against modified clients.
As we get more experience with people using this, we will definitely be thinking about how to make it better by adding power features like these. Thanks for the feedback!