I wonder is it only my license file, or is it applicable to everyone.
If you delete any page in the default nav pages, you will not be able to create that page anymore.
According to temporary table "license permissions", none of the existing forms and pages have insert permission.
But you have permission to delete and modify is available.
Gues, who deleted "contact" page and cannot create it anymore? ](*,)
Solution: had to export all customized objects and restore a SQL backup (did not find any other way of putting back original Contact page into NAV). ](*,)