The mailcap descriptions says: The mailcap file is used by the metamail program. but it is possible to remove mailcap without removing metamail. If the above statement is true, there should be a dependency. If it is false, the statement should be removed or clarified.
not necessarily. If the file is present, metamail will use it. Other programs use it also. However, metamail and other programs have built-in fallbacks if the file is not present, so an explicit dependency is not needed.