diff --git a/doc/bugs/prop__95__isomorphic__95__key__95__encode_fails_with_external_backend_changes.mdwn b/doc/bugs/prop__95__isomorphic__95__key__95__encode_fails_with_external_backend_changes.mdwn
new file mode 100644
index 0000000000..144f76a829
--- /dev/null
+++ b/doc/bugs/prop__95__isomorphic__95__key__95__encode_fails_with_external_backend_changes.mdwn
@@ -0,0 +1,35 @@
+Just a heads up that `prop_isomorphic_key_encode` is failing on master
+(for me locally and at <https://github.com/datalad/datalad-extensions>):
+
+```
+$ git show --no-patch --format=reference
+85e57d826 (Added a comment: streaming data and external backends, 2020-07-30)
+
+$ stack exec -- git annex test -p prop_isomorphic_key_encode
+Tests                     
+  QuickCheck
+    prop_isomorphic_key_encode: FAIL (0.03s)
+      *** Failed! (after 601 tests):
+      Exception:
+        Data.ByteString.last: empty ByteString
+        CallStack (from HasCallStack):
+          error, called at libraries/bytestring/Data/ByteString.hs:1877:23 in bytestring-0.10.8.2:Data.ByteString
+      Exception thrown while showing test case:
+        Data.ByteString.last: empty ByteString
+        CallStack (from HasCallStack):
+          error, called at libraries/bytestring/Data/ByteString.hs:1877:23 in bytestring-0.10.8.2:Data.ByteString
+      
+      Use --quickcheck-replay=896100 to reproduce.
+
+1 out of 1 tests failed (0.03s)
+  (Failures above could be due to a bug in git-annex, or an incompatibility
+   with utilities, such as git, installed on this system.)
+```
+
+I do not see this failure before f75be3216 (external backends wip,
+2020-07-29).
+
+Thanks in advance.
+
+[[!meta author=kyle]]
+[[!tag projects/datalad]]
diff --git a/doc/design/external_backend_protocol/comment_1_7a55199030c3b9f455354139af7dbac0._comment b/doc/design/external_backend_protocol/comment_1_7a55199030c3b9f455354139af7dbac0._comment
new file mode 100644
index 0000000000..09d889d803
--- /dev/null
+++ b/doc/design/external_backend_protocol/comment_1_7a55199030c3b9f455354139af7dbac0._comment
@@ -0,0 +1,8 @@
+[[!comment format=mdwn
+ username="Ilya_Shlyakhter"
+ avatar="http://cdn.libravatar.org/avatar/1647044369aa7747829c38b9dcc84df0"
+ subject="key length"
+ date="2020-07-30T15:13:49Z"
+ content="""
+\"128 bytes maximum\" key length -- maybe a bit shorter to support the E variant?
+"""]]
diff --git a/doc/devblog/day_628__external_key_backends/comment_1_e6ff184245dd1a6cffff2ecdaeff6a66._comment b/doc/devblog/day_628__external_key_backends/comment_1_e6ff184245dd1a6cffff2ecdaeff6a66._comment
new file mode 100644
index 0000000000..09126d2db4
--- /dev/null
+++ b/doc/devblog/day_628__external_key_backends/comment_1_e6ff184245dd1a6cffff2ecdaeff6a66._comment
@@ -0,0 +1,11 @@
+[[!comment format=mdwn
+ username="Ilya_Shlyakhter"
+ avatar="http://cdn.libravatar.org/avatar/1647044369aa7747829c38b9dcc84df0"
+ subject="thanks"
+ date="2020-07-30T15:51:13Z"
+ content="""
+Thanks a lot Joey for implementing this.
+
+\"only had to write around 400 lines of new code\" -- sign of good design.  At some point I'll learn enough Haskell to understand/learn from git-annex's design.
+
+"""]]
diff --git a/doc/todo/external_backends/comment_15_7880557cb94706d82a6d2bfc785288ea._comment b/doc/todo/external_backends/comment_15_7880557cb94706d82a6d2bfc785288ea._comment
new file mode 100644
index 0000000000..322e52f08e
--- /dev/null
+++ b/doc/todo/external_backends/comment_15_7880557cb94706d82a6d2bfc785288ea._comment
@@ -0,0 +1,8 @@
+[[!comment format=mdwn
+ username="Ilya_Shlyakhter"
+ avatar="http://cdn.libravatar.org/avatar/1647044369aa7747829c38b9dcc84df0"
+ subject="streaming data and external backends"
+ date="2020-07-30T15:58:21Z"
+ content="""
+\"I can't think of any situation where git-annex would GENKEY before it has the full content of a file available\" -- if [[todo/git-annex-cat]] were implemented, could then e.g. `git fsck --from REMOTE` without the data ever touching the disk.
+"""]]