^             start at the beginning of the line
([\d\/]+)     match and save a bunch of digits and /'s
.*?           lazily match and ignore stuff until...
(Event.*?ed)  match and save of 'Event...ed'
              match but ignore the following space
\(            match a literal paren
(\d+)         match and save a bunch of digits
\),           match and ignore literal paren, comma, and space
(.*)          match and save anything until...
$             the end of the string