diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
index aeecb48f85cd46e4fc16c387256d0a1e3d8167fd..513f0bc7e1fb13ed392141def8f870a77dd4ed22 100644
--- a/actionpack/lib/action_controller/metal/redirecting.rb
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -68,8 +68,14 @@ def redirect_to(options = {}, response_status = {}) #:doc:
self.response_body = "You are being redirected."
end
- # Redirects the browser to the page that issued the request if possible,
- # otherwise redirects to provided default fallback location.
+ # Redirects the browser to the page that issued the request (the referrer)
+ # if possible, otherwise redirects to the provided default fallback
+ # location.
+ #
+ # The referrer information is pulled from the HTTP `Referer` (sic) header on
+ # the request. This is an optional header and its presence on the request is
+ # subject to browser security settings and user preferences. If the request
+ # is missing this header, the fallback_location will be used.
#
# redirect_back fallback_location: { action: "show", id: 5 }
# redirect_back fallback_location: post