[pcre-dev] Subject length lower bound calculation

Good day!

pcre2test:


PCRE2 version 10.33 2019-04-16
/(?=abc)/I
Capture group count = 0
May match empty string
First code unit = 'a'
Last code unit = 'c'
Subject length lower bound = 0


Why Subject length lower bound = 0, not 3?