ediff-toggle-read-only-function

ediff-toggle-read-only-function is a variable defined in `ediff-init.el'.
Its value is

read-only-mode

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

Documentation:
Function to be used to toggle read-only status of the buffer.
If nil, Ediff tries using the command bound to C-x C-q.