tex: add stuff on testing environment

tex/text.tex

@@ -1661,7 +1661,14 @@ issues.
   \label{fig:integrationtest}
 \end{figure}
 
-\n{2}{Click-ops}
+\n{3}{Testing environment}
+
+The application has been deployed in a testing environment on author's modest
+Virtual Private Server (VPS) at \texttt{https://testpcmt.dotya.ml}, protected
+by \emph{Let's Encrypt} issued, short-lived, ECDSA \texttt{secp384r1} curve TLS
+certificate, and configured with strict CSP. It is a testing instance so limits
+to prevent abuse might be imposed.
+
 
 % =========================================================================== %
 \nn{Conclusion}