Allow Auto Save in Prefab Mode for this project.
When enabled, an Auto Save toggle is displayed in Prefab Mode which you can turn on or off. This is the default. When disabled, there is no Auto Save in Prefab Mode in this project and the toggle is not displayed.
Auto Save can often be convenient and save some clicks, but it may not provide a good experience in cases where saving takes a long time. If there are many such cases in a project, and it is decided that no one working on the project should be using Auto Save, then you can help ensure this by disabling this project setting. It prevents enabling Auto Save by accident, or due to having enabled it while working on a different project.