VMS Help SET, FILE, Qualifiers, /SEMANTICS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /SEMANTICS=semantics-tag
       /NOSEMANTICS

    Use the /SEMANTICS qualifier to create or change a semantics tag.
    Use the /NOSEMANTICS qualifier to remove a semantics tag from a
    file. For more information, refer to the Guide to OpenVMS File
    Applications.