Special:PageProperty is an auxiliary special page that is used when listing the values of one property for one fixed page in cases where the number of these values is too large to fit into Special:Browse. This is a rare case, and it is not considered very useful otherwise to view values of one particular page for one particular property in isolation. To reduce clutter, it has thus been decided to not have this helper special page listed in the overview.

AdminLinks is an independent extension. Please file bugs for it independently.