mailcap-delete-duplicates
mailcap-delete-duplicates is an alias for `delete-dups' in `mailcap.el
'.
(mailcap-delete-duplicates LIST)
Destructively remove `equal' duplicates from LIST.
Store the result in LIST and return it. LIST must be a proper list.
Of several `equal' occurrences of an element in LIST, the first
one is kept.