custom--sort-vars
custom--sort-vars is a compiled Lisp function in `custom.el
'.
(custom--sort-vars VARS)
Sort VARS based on custom dependencies.
VARS is a list whose elements have the same form as the ARGS
arguments to `custom-theme-set-variables'. Return the sorted
list, in which A occurs before B if B was defined with a
`:set-after' keyword specifying A (see `defcustom').