blink-matching-check-function is a variable defined in `simple.el'.
Its value is

  • This variable may be risky if used as a file-local variable.

Function to check parentheses mismatches.
The function takes two arguments (START and END) where START is the
position just before the opening token and END is the position right after.
START can be nil, if it was not found.
The function should return non-nil if the two tokens do not match.