VMS Help DSR, DSR Flags, Overstrike  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    When the Overstrike flag (%) is turned on and inserted between
    two characters, it causes the first of the two characters to be
    overstruck by the following one. By default, the Overstrike flag
    is disabled.

    This capability allows the printing of characters not normally
    available, for example, a European 7, which is a 7 overstruck
    with a hyphen.

    Three or more characters can be overstruck, but only if you
    specify the /BACKSPACE qualifier in the DSR command line.
    Otherwise, only the first and last characters in an overstrike
    sequence will appear.

    The action performed by this flag (as opposed to the flag's
    recognition) can be disabled and reenabled by the .DISABLE
    OVERSTRIKING and .ENABLE OVERSTRIKING commands.

1 - Default

    Recognition is turned off. To turn on recognition, you must use
    the .FLAGS OVERSTRIKE command.