/sys$common/syshlp/helplib.hlb HELP, /MESSAGE, Qualifiers, /FACILITY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    /FACILITY=?
    /FACILITY=(facility-name [,...])
    /FACILITY=ALL

    Specifies which facilities in the database are to be searched
    for a match.

    Enter /FACILITY=? to output a list of all facilities in the
    default database or in a database specified by /LIBRARY.

    To narrow your search, specify one or more facility names
    with /FACILITY. (Multiple facilities must be enclosed in
    parentheses and be separated by commas.) Help Message then
    outputs only matching messages produced by the specified
    facility or facilities.

    Specify /FACILITY=ALL to output messages for all facilities
    in the database. /FACILITY=ALL is the default unless another
    facility is implied; for example, specifying /STATUS or
    defaulting to the value of the CLI symbol $STATUS automatically
    identifies a specific facility. Similarly, cutting and pasting
    a message that includes a facility name invalidates use of the
    /FACILITY qualifier.