vim-55/runtime/scripts.vim

191     " - "diff" in first line (context diff)
193     " - "--- " in first line and "+++ " in second line (unified diff).
194     " - "*** " in first line and "--- " in second line (context diff).
195     " - "# It was generated by makepatch " in the second line (makepatch diff).
197     " - "=== ", line of "=", "---", "+++ " (SVK diff)
198     " - "=== ", "--- ", "+++ " (bzr diff, common case)
199     " - "=== (removed|added|renamed|modified)" (bzr diff, alternative)
200   elseif s:line1 =~ '^\(diff\>\|Only in \|\d\+\(,\d\+\)\=[cda]\d\+\>\|# It was generated by makepatch \|Index:\s\+\f\+\r\=$\|===== \f\+ \d\+\.\d\+ vs edited\|==== //\f\+#\d\+\)'
205 	\ || (s:line1 =~ '^=== \(removed\|added\|renamed\|modified\)')
206     set ft=diff
328   " CVS diff
335       set ft=diff