ediff-match-diff-line

ediff-match-diff-line is a variable defined in `ediff-diff.el'.
Its value is

"^\\([0-9]+\\)\\(\\|,\\([0-9]+\\)\\)\\([acd]\\)\\([0-9]+\\)\\(\\|,\\([0-9]+\\)\\)
?$"

Documentation:
Pattern to match lines produced by diff that describe differences.