VMS Help MACRO, /MIGRATION, Compiler Directives, .LINKAGE PSECT, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 program_section_name

    Name of the program section. The name can contain up to 31
    characters, including any alphanumeric character and the special
    characters underline (_), dollar sign ($), and period (.).