customizecustomize is an interactive autoloaded compiled Lisp function in `
cus-edit.el'. It is bound to <menu-bar> <options> <customize> <customize>.
(customize) Select a customization buffer which you can use to set user options. User options are structured into "groups". Initially the top-level group `Emacs' and its immediate subgroups are shown; the contents of those subgroups are initially hidden.