You can search for identifiers within the package.
in-package search v0.2.0
module Tag = Tezos_stdlib.Tag
val debug : ('a, unit) log
val log_info : ('a, unit) log
val log_notice : ('a, unit) log
val warn : ('a, unit) log
val log_error : ('a, unit) log
val fatal_error : ('a, unit) log
val lwt_debug : ('a, unit Lwt.t) log
val lwt_log_info : ('a, unit Lwt.t) log
val lwt_log_notice : ('a, unit Lwt.t) log
val lwt_warn : ('a, unit Lwt.t) log
val lwt_log_error : ('a, unit Lwt.t) log
val lwt_fatal_error : ('a, unit Lwt.t) log
val event : string Tag.def
val exn : exn Tag.def