When you are submitting your app to Apple app store, there is a section named "Rating" where you should rate your content based on the chart and identify how frequentl
It means that a user of the app can access any URL. The issue is parental controls. If the parent has restricted web access an app that allows unlimited access, that is access to any site the user chooses then the parental controls are subverted.
Once Apple provided parental controls that caused a ripple effect on the capabilities of apps and also required Apple to review all apps for parental control violations. It also means that alternate app stores could not be allowed, they could contain apps that did not properly honor parental controls. Hence:"The Walled Garden."