$ perl -Mre=debug -e'/^CPXX1|^KLXX1|^KMXX1|^MEXX1|^PAXX1|^PMXX1|^SLXX1|^SZXX1|^WXXX1|^YZXX1/'                
Compiling REx `^CPXX1|^KLXX1|^KMXX1|^MEXX1|^PAXX1|^PMXX1|^SLXX1|^SZXX1|^WXXX1|^YZXX1'
size 51 Got 412 bytes for offset annotations.

   1: BRANCH(6)
   2:   BOL(3)
   3:   EXACT <CPXX1>(51)
   6: BRANCH(11)
   7:   BOL(8)
   8:   EXACT <KLXX1>(51)
  11: BRANCH(16)
  12:   BOL(13)
  13:   EXACT <KMXX1>(51)
  16: BRANCH(21)
  17:   BOL(18)
  18:   EXACT <MEXX1>(51)
  21: BRANCH(26)
  22:   BOL(23)
  23:   EXACT <PAXX1>(51)
  26: BRANCH(31)
  27:   BOL(28)
  28:   EXACT <PMXX1>(51)
  31: BRANCH(36)
  32:   BOL(33)
  33:   EXACT <SLXX1>(51)
  36: BRANCH(41)
  37:   BOL(38)
  38:   EXACT <SZXX1>(51)
  41: BRANCH(46)
  42:   BOL(43)
  43:   EXACT <WXXX1>(51)
  46: BRANCH(51)
  47:   BOL(48)
  48:   EXACT <YZXX1>(51)
  51: END(0)
minlen 5 
Offsets: [51]
	0[0] 1[1] 2[5] 0[0] 0[0] 7[1] 8[1] 9[5] 0[0] 0[0] 14[1] 15[1] 16[5] 0[0] 0[0] 21[1] 22[1] 23[5] 0[0] 0[0] 28[1] 29[1] 30[5] 0[0] 0[0] 35[1] 36[1] 37[5] 0[0] 0[0] 42[1] 43[1] 44[5] 0[0] 0[0] 49[1] 50[1] 51[5] 0[0] 0[0] 56[1] 57[1] 58[5] 0[0] 0[0] 63[1] 64[1] 65[5] 0[0] 0[0] 70[0] 
Freeing REx: `"^CPXX1|^KLXX1|^KMXX1|^MEXX1|^PAXX1|^PMXX1|^SLXX1|^SZXX1|^WX"......'

$ perl -Mre=debug -e'/^(?:CPXX1|KLXX1|KMXX1|MEXX1|PAXX1|PMXX1|SLXX1|SZXX1|WXXX1|YZXX1)/'                     
Compiling REx `^(?:CPXX1|KLXX1|KMXX1|MEXX1|PAXX1|PMXX1|SLXX1|SZXX1|WXXX1|YZXX1)'
size 43 Got 348 bytes for offset annotations.
first at 2
   1: BOL(2)
   2: BRANCH(6)
   3:   EXACT <CPXX1>(43)
   6: BRANCH(10)
   7:   EXACT <KLXX1>(43)
  10: BRANCH(14)
  11:   EXACT <KMXX1>(43)
  14: BRANCH(18)
  15:   EXACT <MEXX1>(43)
  18: BRANCH(22)
  19:   EXACT <PAXX1>(43)
  22: BRANCH(26)
  23:   EXACT <PMXX1>(43)
  26: BRANCH(30)
  27:   EXACT <SLXX1>(43)
  30: BRANCH(34)
  31:   EXACT <SZXX1>(43)
  34: BRANCH(38)
  35:   EXACT <WXXX1>(43)
  38: BRANCH(42)
  39:   EXACT <YZXX1>(43)
  42: TAIL(43)
  43: END(0)
anchored(BOL) minlen 5 
Offsets: [43]
	1[1] 4[1] 5[5] 0[0] 0[0] 10[1] 11[5] 0[0] 0[0] 16[1] 17[5] 0[0] 0[0] 22[1] 23[5] 0[0] 0[0] 28[1] 29[5] 0[0] 0[0] 34[1] 35[5] 0[0] 0[0] 40[1] 41[5] 0[0] 0[0] 46[1] 47[5] 0[0] 0[0] 52[1] 53[5] 0[0] 0[0] 58[1] 59[5] 0[0] 0[0] 63[0] 65[0] 
Freeing REx: `"^(?:CPXX1|KLXX1|KMXX1|MEXX1|PAXX1|PMXX1|SLXX1|SZXX1|WXXX1|Y"......'