<item>the literal text <item> (case sensitive) *?matches any number of characters from the set below:
\sany whitespace character
\Sany non-whitespace character
<sub>the literal text <sub> (case sensitive) .*?any character (except for line terminators), repeated any number of times
<the literal < (6010 / 748 / 3C16)
\/the literal / (4710 / 578 / 2F16)
sub>the literal text sub> (case sensitive) Group 2((?!<sub>)[\s\S])* *repeats the group contents below any number of times:
Negative Lookahead(?!<sub>) <sub>the literal text <sub> (case sensitive) \sany whitespace character
\Sany non-whitespace character
<the literal < (6010 / 748 / 3C16)
\/the literal / (4710 / 578 / 2F16)
item>the literal text item> (case sensitive) g modifier: global. Finds all matches instead of stopping after the first