### Enable or disable `HEAD` comparison mode **(CORE ONLY)**
`HEAD` comparison mode is under development and not ready for production use. It is
deployed behind a feature flag that is **disabled by default**.
[GitLab administrators with access to the GitLab Rails console](../../../administration/troubleshooting/navigating_gitlab_via_rails_console.md#starting-a-rails-console-session)
can enable it for your instance. You're welcome to test it, but use it at your
own risk.
To enable it:
```ruby
Feature.enable(:diff_compare_with_head)
```
To disable it:
```ruby
Feature.disable(:diff_compare_with_head)
```
<!-- ## Troubleshooting
Include any troubleshooting steps that you can foresee. If you know beforehand what issues