backward-up-list is an interactive compiled Lisp function in `lisp.el'.

It is bound to <C-M-up>, C-M-u, ESC <C-up>.

(backward-up-list &optional ARG ESCAPE-STRINGS NO-SYNTAX-CROSSING)

Move backward out of one level of parentheses.
This command will also work on other parentheses-like expressions
defined by the current language mode. With ARG, do this that
many times. A negative argument means move forward but still to
a less deep spot. If ESCAPE-STRINGS is non-nil (as it is
interactively), move out of enclosing strings as well. If
NO-SYNTAX-CROSSING is non-nil (as it is interactively), prefer to
break out of any enclosing string instead of moving to the start
of a list broken across multiple strings. On error, location of
point is unspecified.