eXtreme Unit Buttons 

destination    	MB-Target    	KB-Target
-----------------------------------------------
frameunit	LeftClick 	no modifier
player	    	RightClick	ALT
target	    	MiddleClick	SHIFT
focus	    	Button4Click	CTRL
		
rank		MB-Ranked mode 	KB-Ranked mode
-----------------------------------------------
max 		LeftClick	no modifier
middle	    	RightClick	ALT
Rank 1	    	MiddleClick	SHIFT


Examples showing how ranking will be defined (can only be defined in 'Custom Buttons'):
CB_Renew1,buff,Renew,,Renew                        [eg. a standard button]
CB_Renew2,buff,Renew,MB-Ranked,Renew
CB_Renew3,buff,Renew,KB-Ranked,Renew
CB_Macro1,macro,496,/cast [button:2,target=player] Renew; [help] Renew
		
Examples showing how targeting will be defined (can only be defined in 'Group Specifications'):
group1,CB_Renew,*                        [eg. a standard button]
group2,CB_Renew,MB-Target		
group3,CB_Renew,KB-Target
group4,CB_Renew2,KB-Target
group5,CB_Renew3,MB-Target

for Debuffs:
name, rank, texture, count, debuffType, duration, timeLeft  =  UnitDebuff(unitID, debuffIndex [, removable]);
and for Buffs:
name, rank, texture, count, duration, timeLeft =  UnitBuff(unit, buffIndex [, castable]);

change for the API UnitBuff:
name, rank, texture, count, buffType, duration, timeLeft  =  UnitBuff(unitID, debuffIndex [, castable]);

        -- Disable the button if it is not in range or valid for the unit or if that unit is in a duel
        if ( myButton.Unit ~= "player" ) then
            local inRange = IsSpellInRange(myButton.FullSpellName,myButton.Unit)
            if ( inRange == nil ) then
                -- this means either (from WoWWiki)
                -- 1. The spell cannot be cast on the unit. i.e. attempting to check range using 'Frostbolt' on a party member will always return 'nil', similarly testing 'Heal' against an enemy target will also return nil.
                -- 2. If the unit is not 'visible' (see API UnitIsVisible) then you will get a nil, and not a '0' as you might expect.
                -- 3. The unit doesnt exist (e.g. 'target' when you have nothing targetted)
                -- 4. The current player does not know this spell (so you cannot use 'Heal' to test 40 yard range for anyone other than a priest)
                myButton.State = STATE_INVALID;
                return;
            elseif ( inRange == 0 ) then
                -- this means the target is not in Range
                myButton.State = STATE_INVALID;
                return;
            end
        end