\ba Unicode word boundary
httpthe literal text http (case sensitive) s?optionally matches the literal s (11510 / 1638 / 7316) (case sensitive)
:the literal : (5810 / 728 / 3A16)
\S+any character that is not Unicode whitespace, repeated at least once
*the literal (3210 / 408 / 2016) , repeated any number of times
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