How to send a custom header?

[sustained]

If you send Accept: application/vnd.github.mercy-preview+json then you get access to some extra stuff e.g. repository topics. So far I couldn't find any way to do this but I'm still searching through the code/docs.

[danwenzel]

I recommend switching to https://github.com/octokit/rest.js. It's better-maintained, and can do what you're looking for