I can't toggle the Enable selective builds under the Settings tab for my app.
The Enable selective builds allows you to only trigger builds if specific files or folders have changed. Bitrise uses a GitHub API to fetch the difference and parse the change paths. We then check whether the trigger is needed or not.
Because this function depends on this GitHub API, it is only available if you use GitHub. It is not available if you are using another git provider, a self-hosted git provider (including GitHub), a cloud-based git provided, or GitHub Enterprise.