According to GitHub approval page, GiHub Oauth plugin requests permissions to the user's private repos. This seems irrelevant and prevents us from using this plugin. We couldn't find how to tweak these permissions.
You can customize requested scopes in the OAuth application configuration in the Jenkins global security configuration.
The scopes we have as default are the minimum required for private repositories. However, you can further restrict the scopes to whatever you want by updating the requested scopes configuration.