diff --git a/src/allmydata/storage/http_client.py b/src/allmydata/storage/http_client.py
index 9a2774aef..65bcd1c4b 100644
--- a/src/allmydata/storage/http_client.py
+++ b/src/allmydata/storage/http_client.py
@@ -134,7 +134,28 @@ class _TLSContextFactory(CertificateOptions):
     Create a context that validates the way Tahoe-LAFS wants to: based on a
     pinned certificate hash, rather than a certificate authority.
 
-    Originally implemented as part of Foolscap.
+    Originally implemented as part of Foolscap.  To comply with the license,
+    here's the original licensing terms:
+
+    Copyright (c) 2006-2008 Brian Warner
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
     """
 
     def __init__(self, expected_spki_hash: bytes):