* comment: Installation guide link for online help.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getOnlineHelpInstallation();

    /**
     * Get the value for the key 'online.help.eol'. <br>
     * The value is, e.g. https://fess.codelibs.org/{lang}/eol.html <br>
     * comment: End-of-life information link for online help.