classthe literal text class (case sensitive) \s+any whitespace character, repeated at least once
A-Zone character from A (6510) to Z (9010) (case sensitive)
\w+any word character, repeated at least once
\s+any whitespace character, repeated at least once
Non-Capturing Group(?:<\s+(\w+))? ?repeats the group contents below at most once:
<the literal < (6010 / 748 / 3C16)
\s+any whitespace character, repeated at least once
\w+any word character, repeated at least once
\s*any whitespace character, repeated any number of times
{the literal { (12310 / 1738 / 7B16)
*?matches any number of characters from the set below:
\sany whitespace character
\Sany non-whitespace character
\na line-feed (newline) character (ASCII 10)
}the literal } (12510 / 1758 / 7D16)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string