Two thoughts:

1. `use_GitLink` => `useGitLink`, and I'd suggest a default of `true` to mimic git core. (At least I think that's what git core does by default?)
2. I'd rename `branch` as `committish` for consistency with other similar parameters, and set the default to `null` (the repo may not be configured to prefer `master` - we should respect the clone's default if a ref is not specified).