use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new(
    qr/branch\sfrom(.*\/(.*))\#\,(\#\d+)$/xms
)->explain
__END__
The regular expression:

(?msx-i:branch\sfrom(.*/(.*))\#\,(\#\d+)$)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?msx-i:                 group, but do not capture (with ^ and $
                         matching start and end of line) (with .
                         matching \n) (disregarding whitespace and
                         comments) (case-sensitive):
----------------------------------------------------------------------
  branch                   'branch'
----------------------------------------------------------------------
  \s                       whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
  from                     'from'
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    .*                       any character (0 or more times (matching
                             the most amount possible))
----------------------------------------------------------------------
    /                        '/'
----------------------------------------------------------------------
    (                        group and capture to \2:
----------------------------------------------------------------------
      .*                       any character (0 or more times
                               (matching the most amount possible))
----------------------------------------------------------------------
    )                        end of \2
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  \#                       '#'
----------------------------------------------------------------------
  \,                       ','
----------------------------------------------------------------------
  (                        group and capture to \3:
----------------------------------------------------------------------
    \#                       '#'
----------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
----------------------------------------------------------------------
  )                        end of \3
----------------------------------------------------------------------
  $                        before an optional \n, and the end of a
                           "line"
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
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