How to access non-capturing groups

Question

As it cannot be accessed through group index

Answer 1

They're...not captured. You might try running the regex on the target, with only the non-capturables (remove the capture filter indicator). You should get them all by themselves, unless I'm missing something (totally possible).

Answer 2

Correction: non-capturing groups are captured by group() along with everything else. They are not captured by group(n) and they are not captured by groups() but they ARE captured by group().