What is the difference between a standard UI Review and a manual UI Review?
Standard UI Reviews are linked to a specific pull or merge request and are automatically triggered when you open one. These reviews are only available in linked projects.
Manual UI Reviews are not linked to a pull/merge request and must be triggered manually via the Chromatic UI. They work on any project with UI Review enabled, and they’re the only review type available for unlinked projects.
That said, both types of UI Review use the comparison mechanism.