gitPull():

Add important comment for the case that an remote host key change:
	'git pull' handles the issue itself, and continues to pull the repository
	using the ssh-key provided in the .keys/ directory.

UpdatePTUDevCtrl/git/git_client.cpp

@@ -393,6 +393,38 @@ std::optional<QString> GitClient::gitPull() {
     if (QDir(m_customerRepository).exists()) {
         qInfo() << "BRANCH NAME" << m_branchName;
 
+#if 0
+        IMPORTANT COMMENT:
+
+        If remote host keys are changed, then
+
+        export GIT_SSH_COMMAND="ssh -i /opt/app/tools/atbupdate/.keys/id_ed25519_ptuConfig"
+        git pull
+
+        leads to the following warning/error message:
+
+        @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+        @    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
+        @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+        IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
+        Someone could be eavesdropping on you right now (man-in-the-middle attack)!
+        It is also possible that a host key has just been changed.
+        The fingerprint for the ECDSA key sent by the remote host is
+        SHA256:vOD5jF2hglGktqLhK9ABxfEjwEgIK68/v9erdT05NDQ.
+        Please contact your system administrator.
+        Add correct host key in /home/root/.ssh/known_hosts to get rid of this message.
+        Offending ECDSA key in /home/root/.ssh/known_hosts:1
+        Password authentication is disabled to avoid man-in-the-middle attacks.
+        Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.
+        Agent forwarding is disabled to avoid man-in-the-middle attacks.
+        X11 forwarding is disabled to avoid man-in-the-middle attacks.
+        Already up to date.
+
+        This first part is from ssh itself, and could not be fetched easily, as this
+        process is gone when git itself starts.
+
+        Only the last line is the git message.
+#endif
         Command c("git pull");
         if (c.execute(m_customerRepository)) {
             QString const s = c.getCommandResult().trimmed();