Working with excel - empty fields

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Run this code and let me know what "s" is again?
Macro Test

Code:

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rep(3)
,#region Recorded 07.07.2016 12:29:54
,opt save; opt slowkeys; opt slowmouse; spe 50
,int w1=act(win("Test - Excel" "XLMAIN"))
,lef 864 16 w1 1
,'Cc
,str s.getclip
,out F"s={s}, s.len={len(s)}"
,if(s.len) run (s)
,act w1
,'D