This policy setting allows you to prevent users from overriding the sync interval published by managed SharePoint lists.
If you enable this policy setting, the "Update Limit" checkbox found under File tab | Info | Account Settings | SharePoint List | Change… is disabled, and the user's connected SharePoint lists will only sync as defined by the list's administrator.
If you disable this policy setting, then individual users will be able to override the sync interval by unchecking the "Update Limit" checkbox in the SharePoint List's Options dialog. Defined sync intervals can range from 1 minute to 1440 minutes (a full day).
If you do not configure this policy setting, the user's profile will sync the SharePoint list at a default of 20 minutes or as specified by the administrator of the SharePoint list.