I'm really not a fan of this abstraction that uses GH-specific code in a general promise-based getter you use to query specref (e.g. the parseLink function is GH specific).

I'd much rather you avoided this abstraction altogether (notably because I've extracted the GH stuff in its own repo.: https://github.com/tobie/simple-github) and created a specref dedicated module, which certainly doesn't need all of the GH-boilerplate.