You can search for identifiers within the package.
in-package search v0.2.0
type 'a t = 'a Lwt.t
val return : 'a -> 'a t
val bind : 'a t -> ('a -> 'b t) -> 'b t
val map : ('a -> 'b) -> 'a t -> 'b t
val return_unit : unit t
val return_none : 'a option t
val return_nil : 'a list t
val return_true : bool t
val return_false : bool t