^start of line
\s*any whitespace character, repeated any number of times
subblock
the literal text subblock (case sensitive) +?matches at least one character from the set below:
\sany whitespace character
\Sany non-whitespace character
^start of line
\s*any whitespace character, repeated any number of times
\}the literal } (12510 / 1758 / 7D16)
;the literal ; (5910 / 738 / 3B16)
$end of line
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
x modifier: extended. Ignores unescaped whitespace and comments outside character classes