display-buffer-overriding-action

display-buffer-overriding-action is a variable defined in `window.el'.
Its value is

(nil)

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

Documentation:
Overriding action to perform to display a buffer.
It should be a cons cell (FUNCTION . ALIST), where FUNCTION is a
function or a list of functions. Each function should accept two
arguments: a buffer to display and an alist similar to ALIST.
See `display-buffer' for details.