diff --git a/bin/xbps-install/xbps-install.1 b/bin/xbps-install/xbps-install.1
index 96eebbed..61e8c423 100644
--- a/bin/xbps-install/xbps-install.1
+++ b/bin/xbps-install/xbps-install.1
@@ -99,7 +99,9 @@ than looking in the target root directory.
 Appends the specified repository to the top of the list. The
 .Ar url
 argument expects a URL to the repository for remote repositories or
-a path for local repositories.
+a path for local repositories. Note that remote repositories must be signed
+using
+.Xr xbps-rindex 1 .
 This option can be specified multiple times.
 .It Fl r, Fl -rootdir Ar dir
 Specifies a full path for the target root directory.