I have not exported any function using @EXPORT, but I have used the DEFAULT in %EXPORT_TAG

The :DEFAULT tag applies to @EXPORT. From the Exporter pod:

Advanced features

Specialised Import Lists If any of the entries in an import list begins with !, : or / then the list is treated as a series of specifica- tions which either add to or delete from the list of names to import. They are processed left to right. Specifica- tions are in the form:

           [!]name         This name only
           [!]:DEFAULT     All names in @EXPORT
           [!]:tag         All names in $EXPORT_TAGS{tag} anonymous li
+st
           [!]/pattern/    All names in @EXPORT and @EXPORT_OK which m
+atch
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A leading ! indicates that matching names should be deleted from the list of names to import. If the first specification is a deletion it is treated as though preceded by :DEFAULT. If you just want to import extra names in addition to the default set you will still need to include :DEFAULT explicitly.