diff --git a/README.md b/README.md
index d69a042..95b037f 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,12 @@ doing so. `git remote` sorts alphabetically, so picking the first remote in
 be-edition returns `kdog` — a colleague's fork. nvim's `<leader>gm`
 (diff-against-branch) tries `origin`, then `upstream`, then the rest.
 
+One wrinkle: setting `remote.origin.followRemoteHEAD` at all is enough for git to
+invent the remote, so `git remote` lists a URL-less `origin` in repos that have
+none — this one, whose remotes are `forge` and `github`. It is a listing
+artefact, not a real remote: `git remote get-url origin` still fails, so the
+`origin` guard in `git sync` and the fallbacks in `<leader>gm` behave.
+
 ## Light and dark mode
 
 Most of this is now handled natively and needs no configuration:
diff --git a/gitconfig b/gitconfig
index c4360af..9dcf1f6 100644
--- a/gitconfig
+++ b/gitconfig
@@ -47,6 +47,12 @@
     # branch that may not even exist. `always` re-points it on each fetch, off the
     # ref advertisement that fetch already receives, so it costs no extra round
     # trip. Only applies to remotes actually named origin.
+    #
+    # Side effect: git conjures a remote from the existence of any remote.<name>.*
+    # key, so this makes `git remote` list a URL-less origin in every repo that
+    # has not got one - this repo included. Nothing breaks (`git remote get-url
+    # origin` still says No such remote, which is what the scripts test), but do
+    # not read that listing as evidence a real origin exists.
     followRemoteHEAD = always
 
 [core]