You can search for identifiers within the package.
in-package search v0.2.0
val return : 'a -> 'a option
val fail : 'a option
val return_unit : unit option
val return_nil : 'a list option
val return_true : bool option
val return_false : bool option
val let* : 'a option -> ('a -> 'b option) -> 'b option
val and* : 'a option -> 'b option -> ('a * 'b) option
val let+ : 'a option -> ('a -> 'b) -> 'b option
val and+ : 'a option -> 'b option -> ('a * 'b) option
val both : 'a option -> 'b option -> ('a * 'b) option