+/[^\xff]*PRUNE:\x{100}abc(xyz(?1))/8DZ
+------------------------------------------------------------------
+ Bra
+ [^\x{ff}]*
+ PRUNE:\x{100}abc
+ CBra 1
+ xyz
+ Recurse
+ Ket
+ Ket
+ End
+------------------------------------------------------------------
+Capturing subpattern count = 1
+Options: utf
+No first char
+Need char = 'z'
+
+/(?<=\K\x{17f})/8g+
+ \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}
+ 0: \x{17f}
+ 0+
+
+/(?<=\K\x{17f})/8G+
+ \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}
+ 0: \x{17f}
+ 0+
+