^start of line
Non-Capturing Group(?:username|Email|Url) usernamethe literal text username (case insensitive) Emailthe literal text Email (case insensitive) Urlthe literal text Url (case insensitive) :?optionally matches the literal : (5810 / 728 / 3A16)
*the literal (3210 / 408 / 2016) , repeated any number of times
\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match
\V+any character that's not a vertical whitespace character, repeated at least once
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
i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters