STRONG or VERY STRONG keyword syntax meaning in sybase script

Question

Below is a partial codes of a sybase database script for matching some security reference data related various files and then DML operation. My prior experience are in Oracle so I wanted to know what are the special meaning of this [STRONG] or [VERY STRONG] keyword syntax in this below sybase script.

#---------------------------------------------#
#          PDP INSERTION                      #
#---------------------------------------------#
ON NEW pdp SECURITY
        DECLARE MATCH SECURITY: SECURITY_MATCH
    DECLARE CHAR: LOCAL_EXC_1
        DECLARE CHAR: LOCAL_TICKER_1
        DECLARE CHAR: LOCAL_EXC_2
    DECLARE CHAR: LOCAL_COUNTRY_1
    DECLARE CHAR: LOCAL_SEDOL_1
        DECLARE MATCH SECURITY ALLOW_VENDOR_COLLISIONS: PKEY_MATCH


    IF $EXC = "HONG_KONG" AND LEFT($LOCAL_ID,4) = "HE!0" THEN
        LOCAL_TICKER_1 = RIGHT($LOCAL_ID, STRLEN($LOCAL_ID) - 4) 
    ELSE
        LOCAL_TICKER_1 = RIGHT($LOCAL_ID, STRLEN($LOCAL_ID) - 3)
    ENDIF


        #-----------------------------#
        # PRIMARY KEY CHECK - CHECKS  #
        # FOR A DUPLICATE PRIMARY KEY.#
        #-----------------------------#

        PKEY_MATCH = MATCH SECURITY
           $VALOREN = pdp.VALOREN
        END MATCH

    #--------------#
        # SEDOL MATCH  #
        #--------------#
        IF SECURITY_MATCH.NUMBER = 0 AND $SEDOL != NULL AND $EXC != NULL THEN
              SECURITY_MATCH = MATCH SECURITY
                    MUST LOCAL_SEDOL_1 = SEDOL [VERY STRONG]
                    MUST LOCAL_EXC_1 = EXC OR
                         LOCAL_COUNTRY_1 = COUNTRY_TRADE [STRONG]
                    MUST ACTIVE = 1 [STRONG]
              END MATCH
        ENDIF

    #-------------#
        # ISIN MATCH  #
        #  INDEXES    #
    #-------------#

         IF $ISIN != NULL AND $TYPE = 34 AND SECURITY_MATCH.NUMBER = 0 THEN
                SECURITY_MATCH = MATCH SECURITY
                 MUST $ISIN = ISIN [VERY STRONG]
                 MUST EXC = "ZZZ" [STRONG]
                MUST ACTIVE = 1 [STRONG]
          END MATCH
        ENDIF

PRINT( "PKEY_MATCH.NUMBER IS: ", PKEY_MATCH.NUMBER)
PRINT ("ISIN IS: ", $ISIN)
PRINT ("EXC IS: ", $EXC)
PRINT ("LOCAL_EXC_1 IS:", LOCAL_EXC_1)
PRINT ("$LOCAL_ID IS: ", $LOCAL_ID)

  IF PKEY_MATCH.NUMBER = 0 THEN
        ADD_VENDOR_ROW(SECURITY_MATCH)
  ENDIF