diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 0108a0407a..4e43ca7f65 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -616,7 +616,10 @@ set to `${sAMAccountName.toLowerCase}`). It is important that for all
 existing accounts this username is already in lower case. It is not
 possible to convert the usernames of the existing accounts to lower
 case because this would break the access to existing per-user
-branches.
+branches and Gerrit provides no tool to do such a conversion.
++
+Setting this parameter to `true` will prevent all users from login that
+have a non-lower-case username.
 +
 This parameter only affects git over http and git over SSH traffic.
 +
diff --git a/Documentation/pgm-LocalUsernamesToLowerCase.txt b/Documentation/pgm-LocalUsernamesToLowerCase.txt
index 03aaabfe70..4b50961893 100644
--- a/Documentation/pgm-LocalUsernamesToLowerCase.txt
+++ b/Documentation/pgm-LocalUsernamesToLowerCase.txt
@@ -14,7 +14,11 @@ _java_ -jar gerrit.war _LocalUsernamesToLowerCase_
 == DESCRIPTION
 Converts the local username for every account to lower case. The
 local username is the username that is used to login into the Gerrit
-Web UI.
+Web UI. The local username is stored a external ID with scheme
+`gerrit`.
+
+[IMPORTANT]
+This program does not modify usernames in the `username` scheme.
 
 This task is only intended to be run if the configuration parameter
 link:config-gerrit.html#ldap.localUsernameToLowerCase[ldap.localUsernameToLowerCase]