+These extra bindings are located in the
+`reftex-extra-bindings-map' map, bound to
+`reftex-extra-bindings-prefix'."
+ :group 'reftex-miscellaneous-configurations
+ :type 'boolean)
+
+;; below, default is C-c C-y because it is free in LaTeX mode.
+(defcustom reftex-extra-bindings-prefix "\C-c\C-y"
+ "When `reftex-extra-bindings' is set to non-nil, use extra
+bindings with this prefix bound to `reftex-extra-bindings-map'."