You can search for identifiers within the package.
in-package search v0.2.0
type (!'ok, !'err) t =
| Ok of 'ok
| Error of 'err
val return : 'a -> ('a, 'b) t
val bind : ('a, 'b) t -> ('a -> ('c, 'b) t) -> ('c, 'b) t
val (>>=) : ('a, 'b) t -> ('a -> ('c, 'b) t) -> ('c, 'b) t
val fail : 'a -> ('b, 'a) t