apropos-user-option is an interactive autoloaded compiled Lisp function in `
It is bound to <menu-bar> <help-menu> <search-documentation> <find-options-by-name>.
(apropos-user-option PATTERN &optional DO-ALL)
Show user options that match PATTERN.
PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters). If it is a word,
search for matches for that word as a substring. If it is a list of words,
search for matches for any two (or more) of those words.
With C-u prefix, or if `apropos-do-all' is non-nil, also show
variables, not just user options.