diff --git a/requests/sessions.py b/requests/sessions.py
index 6d51820c..cd8a8ae6 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -95,10 +95,6 @@ def merge_hooks(request_hooks, session_hooks, dict_class=OrderedDict):
 
 class SessionRedirectMixin(object):
 
-    def __init__(self):
-        #: A list of domains that will be excluded from auth stripping
-        self.trusted_domains = []
-
     def get_redirect_target(self, resp):
         """Receives a Response. Returns a redirect URI or ``None``"""
         # Due to the nature of how requests processes redirects this method will
@@ -124,8 +120,7 @@ class SessionRedirectMixin(object):
         """Decide whether Authorization header should be removed when redirecting"""
         old_parsed = urlparse(old_url)
         new_parsed = urlparse(new_url)
-        if (old_parsed.hostname != new_parsed.hostname
-                and new_parsed.hostname not in self.trusted_domains):
+        if old_parsed.hostname != new_parsed.hostname:
             return True
         # Special case: allow http -> https redirect when using the standard
         # ports. This isn't specified by RFC 7235, but is kept to avoid
@@ -419,8 +414,6 @@ class Session(SessionRedirectMixin):
         self.mount('https://', HTTPAdapter())
         self.mount('http://', HTTPAdapter())
 
-        super().__init__()
-
     def __enter__(self):
         return self