browse-url-process-environment
browse-url-process-environment is a compiled Lisp function in `browse-url.el
'.
(browse-url-process-environment)
Set DISPLAY in the environment to the X display the browser will use.
This is either the value of variable `browse-url-browser-display' if
non-nil, or the same display as Emacs if different from the current
environment, otherwise just use the current environment.