^start of line
LTEthe literal text LTE (case sensitive) RSthe literal text RS (case sensitive) +matches at least one character from the set below:
A-Zone character from A (6510) to Z (9010) (case sensitive)
\s*a Unicode whitespace character, repeated any number of times
Negated Character Class[^:]+ +matches at least one character outside the set below:
:the literal : (5810 / 728 / 3A16)
:the literal : (5810 / 728 / 3A16)
\s+a Unicode whitespace character, repeated at least once
.*?any Unicode character (except for line terminators), repeated any number of times
Positive Lookahead(?=\s*$) \s*a Unicode whitespace character, repeated any number of times
$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