why is there so many deps in the dev/user.clj in edge repo?

(ns user
  (:require
   [clojure.pprint :refer [pprint]]
   [clojure.test :refer [run-all-tests]]
   [clojure.reflect :refer [reflect]]
   [clojure.repl :refer [apropos dir doc find-doc pst source]]
   [clojure.tools.namespace.repl :refer [refresh refresh-all]]
   [ :as io]
   [com.stuartsierra.component :as component]
   [clojure.core.async :as a :refer [>! <! >!! <!! chan buffer dropping-buffer sliding-buffer close! timeout alts! alts!! go-loop]]
   [edge.system :as system]
   [reloaded.repl :refer [system init start stop go reset reset-all]]
   [schema.core :as s]
   [yada.test :refer [response-for]]))

The` user` namespace is for the developer, and brings in lots of useful functions into the environment. Possibly the async ones aren't necessary - I think they were used in a training course

@malcolmsparks okay thanks

what does line 120 in edge/build.boot do

(set-env! :dependencies #(vec (concat % '[[reloaded.repl "0.2.1"]])))